List of Hey Arnold! characters

Main characters

Arnold Shortman

Gerald Johanssen

Helga Pataki

Supporting characters

• Phoebe Heyerdahl – The smartest girl in Arnold's class. She's Helga's 9-10 year old best friend and confidante, though Helga tends to boss her around. Nevertheless, Phoebe acts sometimes as Helga's moral compass, advising her on what she should do. Her ethnicity is half-Japanese on her father's side and her mother is white. She is from Kentucky. Being the smartest girl in her class is very important for her, and she tries her hardest to be that way. Throughout the series, both she and Gerald have a love interest in one another, with Gerald implying a crush on her during Rhonda's party in the episode "Hey Harold". In Hey Arnold!: The Jungle Movie, Phoebe kisses Gerald and are both seen holding hands at the movie's end, having finally admitted their feelings for one another.
• Harold Berman – A Jewish American friend of Arnold. Although portrayed as the school bully during the first season, he became more of a companion to Arnold and the other kids later on as his antagonistic role increasingly shifted over to Wolfgang. Despite his frequent bullying and intimidation of other students, Harold's bullying never involves stealing lunch money and he's often revealed to be rather cowardly and usually cries for his mother whenever he gets scared or upset. He's sometimes referred to by the derisive nickname "fat boy", usually by Helga. He is overweight and in later episodes it's revealed that Harold has a soft spot. His best friends are Sid and Stinky.
• Stinky Peterson – Stinky is a tall and lanky friend of Arnold's whose family is from Arkansas, and he is also one of Harold's best friends. Stinky has a Southern accent and a love for lemon pudding. His friendship with Harold had him originally portrayed in the first season as a bully who wore spiked wristbands and sidekick of Harold's, though the former was later de-emphasized and he was reinvented as a more affectionate, mild mannered and romantic character viewed as the class "ladies man", as he's romantically attracted to several female characters. He's shown to make up excellent poems while Phoebe was feeling depressed.
• Sid – A 9-10 year old friend of Arnold and one of Harold's best friends with paranoid tendencies. He is always shown wearing a green baseball cap backwards, a black leather jacket, jeans and a pair of white Beatle boots. He often tells urban legends, with or without the assistance of Gerald. Perhaps his most well-known characteristic is that he typically ends up in ridiculous situations, such as becoming severely mysophobic, deciding to devote his life to Arnold after Arnold saves his life, and believing Stinky is a vampire, among other things.
• Rhonda Wellington Lloyd – A 9-10 year old rich, pompous, self-proclaimed fashion queen and friend of Arnold. She is one of the most popular students attending P.S. 118. Both of her parents are stereotypically preppy. Even though she is always seen concerned about her style, Rhonda is a phenomenal athlete, practicing numerous contact sports, like baseball and football, not caring if she ruins her clothes or accessories.
• Eugene Horowitz – A somewhat socially inept but optimistic friend of Arnold, the class jinx. Eugene is prone to several forms of misfortune and is often bullied. He believes Arnold is a jinx due to several of his past tragedies having occurred in Arnold's presence. It's implied that he has a crush on Sheena.
• Lila Sawyer – A 9-10 year old nice girl who came from a fictional farming community she calls "Pleasantville" and who lives with her father. Her mother is never seen or mentioned probably because she and Lila's father are divorced or she died. She is Arnold's crush. However, she only prefers Arnold as a friend. She had a crush on Arnold's cousin Arnie. She knows that Helga loves Arnold and offered to help Helga become more like her in one episode. She is described by the show's creator as being a foil for Helga, someone who tries to suppress her darker side by acting overtly nice and sweet similarly to how Helga tries to cover her kind, sensitive side with bullying.

  Sunset Arms boarders

• Oskar Kokoshka – A lazy, inconsiderate, mooching immigrant from an Eastern European country, that remains unemployed through most of the series, until becoming a paperboy. He has a gambling problem, does not do what he promised, is unable to read the English language until getting assistance from Arnold, and is a pathological liar, even taking advantage of Arnold who often tries to help him out. His childish demeanor and whininess often irritate others. Despite all his negative, despicable personality traits, he does love his wife and feels really bad when he thinks he has let somebody down. His voice resembles that of comedian Yakov Smirnoff and he occasionally utters Smirnoff's catchphrases. He shares his name with an Austrian artist.
• Suzie Kokoshka – Oscar's hard-working, dedicated, mature, loving and caring wife, who puts up with all of her husband's antics, selfishness, and laziness, though the two occasionally fight. In the episode "Baby Oskar" she has a cousin named Nancy and a nephew who is also named Oskar and was babysitting him for two days.
• Ernie Potts – A short-statured and hot-headed demolitionist who has a Napoleon complex. In the episode "Ernie in Love" he develops a crush and starts dating a plus-size model named Lola.
• Mr. Hyunh – His last name is pronounced "win." He is an immigrant from Vietnam, working in a Mexican restaurant. Despite having a heavy Vietnamese accent when speaking, it is revealed that he's very talented at singing country music with the singing voice provided by country singer Randy Travis. He can also play cello, guitar and trumpet quite well. One episode reveals that he has a long lost daughter, Mai, whom he was separated from after he had asked a US soldier to take her out of Vietnam during the Fall of Saigon. They are finally reunited in the Christmas special "Arnold's Christmas", courtesy of Arnold, Gerald, and Helga. Mai's biological mother is never seen or mentioned, and no explanation is given for her absence.
• Mr. Smith – A mysterious character who lived in the boarding house. His face is never seen, nor has his voice ever been heard. He is resented by the other boarders due to this secretive lifestyle, as he does not share many of the main boarding house facilities, which are limited, based on the number who live there. He only appears in the first season.
• Lana Vail – A lawyer who resides in the boarding house. She wears a purple suit and has brown hair. She was a minor character to begin with, and has brief appearances throughout the series. She has her only speaking appearance in "Heat".
• Mr. Purdy – he is only mentioned once in the episode "Gerald Comes Over" when Arnold collects the rent money. There are suspicions of him sharing his room with a chicken, this from chicken noises as Gerald listens from outside his door, never revealed, but covered up by him.

  Families

Shortman family

• Phillip "Phil" Shortman – Arnold's cheery, fun-loving grandfather. He is 81 years old, as of the episode "Grandpa's Birthday". Arnold often comes to him for advice. He often tells Arnold stories about his past experiences, although he has a tendency to stretch the truth. Despite responding frivolously to Arnold's problems, he will often provide good wisdom. While his advice isn't usually the most helpful, his heart is always in the right place. He's a World War II veteran and claims to have single-handedly won the Battle of the Bulge by tricking a large troupe of Nazi soldiers into eating numerous cans of spoiled CHAM, thereby poisoning them and creating a hole in the enemy line for the American troops to break through. Arnold does not believe his story at first, but it's later proven when Phil shows him a small monument of him hidden in some bushes in a park in Washington D.C. Phil was also a master at Chinese checkers in his youth, which earned him the nickname "Steely Phil". He's very healthy and spry for his age, as well as athletic. He has an older twin sister named Mitzi. When he and Mitzi were kids they used to be really close and they owned a Scottish Terrier named Pooter but one day he got out of their backyard and was killed by a milk truck and after that day he and Mitzi stopped speaking to each other for 71 years.
• Gertrude "Pookie" Shortman – Arnold's wacky but wise grandmother who is often seen doing outlandish things, including dressing up and acting like fictional and historic figures, such as Calamity Jane. She is called "Pookie" by Grandpa Phil and Gertie by Aunt Mitzi She has a black belt. She and Phil had a similar relationship that Helga and Arnold have when they were Arnold's age.
• Miles and Stella Shortman – Arnold's parents, Miles being Phil and Gertrude's son. They're adventurous and brave, though Miles appears to be clumsy and tends to end up hurt. They met while exploring in San Lorenzo, where they occasionally crossed paths with the Green-Eyed people, a mysterious indigenous tribe. They returned to the city after Arnold's birth, but were called back for "a final mission" when a friend informed them that the Green Eyes were in trouble; they failed to return, leaving their son under his grandparents' care. Arnold comes across a journal detailing some of their adventures years afterwards. His pet pig, Abner, was a wedding gift to his parents from the Green Eyes. In The Jungle Movie, it is revealed that while trying to cure the adults of the Green Eyes who had caught the sleeping sickness they ran out of medicine and began to work on making more, but unfortunately, they ended up contracting sleeping sickness leaving only the Green Eyes' children to watch over them and the other adults. However, they managed to make enough of the cure and planned to aerosolize it so it could cure everyone using the Green Eyes' technology which was activated by the Corazon, a literal heart made of solid gold which was sought by the villainous river pirate Lasombra who pretends to be Miles and Stella's friend Eduardo to trick him in leading him to the Corazon. However, the Corazon falls down a ravine while Arnold, Helga, Gerald, and the real Eduardo are struggling with Lasombra. Fortunately, Helga gets the idea to use her locket in place of the Corazon which she reveals to Arnold for the first time. It worked and the cure is released curing the Green Eyes and Arnold's parents who return home with their son.
• Arnie – Arnold's cousin, who lives in the countryside and strongly resembles Arnold. He likes to collect lint and gum, count things, read the ingredients on the back of food containers, and makes a peculiar snorting sound on occasion. When he visits PS. 118, Lila develops a crush on him and attempts to attract his attention, but he develops a crush on Helga. He's often seen as strange, gross, dull or stupid by those around him.
• Mitzi Shortman – Arnold's great aunt, Phil's twin sister and childhood rival. She is 81 years old. When she and Phil were kids they had a Scottish Terrier named Pooter but then was killed by a milk truck and after that day she and her brother stopped speaking to each other for 71 years.
• Grandpa Phil's father – He is often seen in Grandpa's flashbacks to the 1920s.
• Grandpa Phil's grandfather – Having lived from 1830-1921, he is seen in one of Grandpa's flashbacks. Grandpa remembers doing chores one winter while his friends were ice skating, only to be hit with a snowball by his grandfather who gave him permission to stop his chores and play.

  Pataki family

• Robert "Big Bob" Pataki – Olga and Helga's oafish, ambitious entrepreneur father, a successful beeper salesman who owns a beeper store. He has extremely high expectations for Helga and frequently compares her to her older sister Olga. Bob also frequently calls Helga by Olga's name by mistake and is often neglectful to her. However, Bob does care for Helga as is evidenced in subtle ways. Bob has difficulty showing his emotions for Helga since she and he always come into conflict with each other. He often mistakenly calls Arnold "Alfred". In The Jungle Movie, he still sells beepers despite Helga pointing out that nobody uses beepers anymore due to cellphones and it's implied that his business isn't as successful as it used to be.
• Miriam Pataki – Olga and Helga's inattentive mother. It's hinted throughout the show that Miriam suffers from alcoholism, as she often drinks "smoothies" which sometimes contain ingredients found in alcoholic cocktails such as celery and tabasco sauce, forgets things, speaks in a slow, tired voice, has had her driver's license revoked, has to do community service and sleeps a lot. Like Bob, it is shown in very subtle ways that she cares about Helga, such as checking in her room when she heard a crash. The unaired Hey Arnold! spin-off, The Patakis, would have included her struggle with alcoholism and joining of Alcoholics Anonymous as a plot point. However, in one episode when Bob injures his back and cannot work, Miriam fills in for him. During the episode Miriam sobers up and holds the fort. Miriam also becomes more attentive towards Helga until she becomes a workaholic and realizes that she is ignoring Helga. Then, she quits and makes Bob return to work. However, her sobriety doesn't last long because in episodes following this one, she is back to drinking smoothies. Miriam was a champion bull rider before marrying Bob, and she used to be an Olympic class swimmer. She reveals in the episode "Olga Gets Engaged" that she regrets marrying Bob, which resulted in throwing her life away and presumably resulting in her insecurities.
• Olga Pataki – Helga's intelligent, outgoing, beautiful older sister, who attends the fictional Wellington College, although in one episode, Helga says that Olga attends Bennington College, which is an existing college located in the U.S. state of Vermont. Olga clearly suffers from perfectionism. She possesses skills that demonstrate a high level of intelligence, as in the episode "Helga on the Couch", where she is shown to be a virtuoso pianist in one of Helga's flashbacks, and when Helga mentions that she was a straight-A student. She attended P.S. 118 as a child, and is praised by Helga's teachers for her achievements. Bob and Miriam consider Olga perfect, which bothers Helga. They sometimes confuse Helga with Olga. Olga gives Helga more attention than their parents and has good intentions, but Helga doesn't receive Olga's attention or intentions very well and often tries to push Olga away and keep her distance. Olga has a tendency to view life through rose-colored glasses and appears not to even notice Helga's avoidance tactics. It's revealed in "Helga on the Couch" that through the years Olga has reacted to her family's problems by being a perfectionist and keeping quiet about the situations at hand. Therefore, either Olga likes to avoid conflict since she rarely acknowledges her family's problems, is oblivious, or is in denial. She later reveals to Helga that she's envious of her, as unlike Olga, their parents never heaped unrealistic expectations onto Helga, comparing herself to a "wind-up doll" that performs for their parents. In The Jungle Movie she is Mr. Simmons's helper with chaperoning his students on a trip to San Lorenzo. When they arrive, she develops a crush on Che, a shipmate who turns out to be working for Lasombra, and is heartbroken when he locks her and the others up in jail. Later in the movie when her parents and Arnold's grandparents come to help them, Olga tells Big Bob that Che was mean to her and started chasing him and beating him up for breaking her heart.

  Johanssen family

• Martin Johanssen – Gerald's sometimes strict father, complains about wasting electricity. He is a Vietnam War veteran.
• Mrs. Johanssen – Gerald's very kind mother, keeps family together. She is a cashier at the neighborhood market.
• James "Jamie O" Johanssen – Gerald's teenage brother, who bullies him. In the episode "Jamie O in Love" Arnold and Gerald spy on him to find out why he was being so nice to them and found out that he had a girlfriend named Sharice. One day, after Jamie O dropped them off at a restaurant to eat lunch, they see Sharice and overhear a conversation between her and her friend that she does not really like Jamie O and was gonna milk him for all he is worth. Gerald tells Arnold not to say anything about it to him because they're worried if he told them that he'd stop being nice and would not drive them to an upcoming hockey game. Days later Jamie O is seen doing Sharice's laundry and making her a soufflé. While juggling to do all those things, Jamie O accidentally burns one of Sharice's cashmere socks and breaks down crying. Feeling conflicted, Gerald decided to tell Jamie O the truth about Sharice and he doesn't believe him until he overheard her talking to her friend that he's a sap, causing Jamie O to realize that Gerald was right, and as a result, Jamie O broke up with her offscreen. The next day, to show that he's sorry for not believing his brother, Jamie O drives Gerald and Arnold to the hockey stadium.
• Timberly Johanssen – Gerald's little sister. She usually causes trouble due to her desire for attention or naturally childish behaviour. Unlike all the other children on the show, Timberly seems to age throughout the series. In her first appearance, she's four years old, but she already attends the first grade in "Timberly Loves Arnold", although this may be a continuity error, rather than intentional.

  Heyerdahl family

• Kyo Heyerdahl – Phoebe's Japanese American father. He speaks Japanese fluently. However, his surname is not Japanese, it is Norwegian.
• Reba Heyerdahl – Phoebe's Southern American mother from Kentucky.

  Berman family

• Jerry Berman – Harold's father. He has a tendency of talking in a very low pitch, and is more concerned about Harold's obesity than his wife.
• Marilyn Berman – Harold's mother. She is more vocal with her scolding of Harold than her husband.

  Horowitz family

• Nate Horowitz – Eugene's father. He is equally unlucky as his son as seen in the episode "Fishing Trip".
• Mrs. Horowitz – Eugene's mother who, unlike Eugene and her husband who are redheads, is the only member of their family with blonde hair.

  Lloyd family

• Buckley Lloyd – Rhonda's father. Whenever Rhonda gets very upset, he buys her things to cheer her up.
• Brooke Lloyd – Rhonda's mother who believes her daughter is a perfect angel who can do no wrong. Most episodes she's seen talking on her cellphone.

  Sawyer family

• Mr. Sawyer – Lila's father is seen in the episode "Ms. Perfect". He appears to be a kind and caring father. When Lila is new to P.S. 118 and being bullied by some of her female classmates, her father tries to be there for her. In the episode it is revealed that he had been unemployed and it ends happily with him getting a job.

  Other characters

Other students of PS 118

• Thaddeus "Curly" Gammelthorpe – The class sociopath. He has had meltdowns and outbursts throughout the show such as in the episodes "False Alarm" and "Curly Snaps". He also appears to have a major crush on Rhonda. In the episode "Curly's Girl", Rhonda pretends to be Curly's girlfriend for a week after he cleaned her mother's new mink coat she wore for a school art show, but she is disgusted by his appeal.
• Torvald – A fourth grader who was held back for several years due to his poor math performance and is considerably older than the rest of the students. He is tutored by Arnold in one episode. In the episode "Tutoring Torvald", he is revealed to be 13 years old. He disappears from the series after Season 2.
• Sheena Annapotato – A geeky girl who does not like violence. Her aunt Shelly is the school nurse, her uncle Earl rows a boat. It is implied that Sheena has a crush on Eugene Horowitz.
• Lorenzo – A wealthy Hispanic American boy who did not have enough time to be a kid, by his mother's schedule. Arnold and the other kids teach him what it means to be a kid. In the episode "Arnold's Room" he and Sid are partners for a science project at school after seeing Lorenzo's bedroom, Sid is worried that his bedroom isn't good enough to show Lorenzo so he borrows Arnold's bedroom so they could work together. At the end of the episode when Arnold and the rest of his guy friends came over to play card games Sid knocks on the door and Lorenzo asks him why he is knocking if it is his own room then breaks down crying after explaining why he lied to him. Lorenzo forgave him if he promises never to lie to him again and to show that everything is hunky-dory Arnold invites them both to join him and the others in playing cards.
• Iggy – A friend of Arnold's who is considered popular amongst his classmates. During the first season, he was shown as something of a troublemaker who would sometimes co-operate with Harold in mischievous deeds. His shirt tails stick out like Arnold's, creating illusion of a kilt, and he almost always wears dark sunglasses that he rarely takes off. Iggy is infamous for the episode "Arnold Betrays Iggy", where his classmates find out he wears pink and white bunny pajamas after Sid and Stinky discover it and he blames Arnold for it, angrily rejecting his apologetic actions until Arnold reluctantly subjects himself to a widely publicized humiliation from many of his kid and adult friends by wearing the same bunny pajamas in front of him in public; during this time, Iggy finds out that Sid and Stinky were the true culprits and tries to apologize to Arnold afterwards, but Arnold only gives him an angry look, implying that he is too angry to forgive him. In later episodes however, there is no continuing animosity between the two as Iggy continued to associate with Arnold, implying that Arnold has either eventually forgiven him or the time has passed long enough to be as if it never happened.
• Brainy – A geek and Helga's stalker who is usually knocked unconscious by Helga without Helga looking at him. He seems to be romantically attracted to her. He has a very deep voice, wheezes noisily, and never talks in a completed sentence. He rarely appears except when Helga looks at her locket containing a picture of Arnold. Apparently Brainy hasn't told anybody else about Helga's crush on Arnold. He has the same hairstyle as Bart Simpson from The Simpsons. In The Jungle Movie", he continues to stalk Helga though he ends up helping her by retrieving her locket and Arnold's torn up picture which Helga discarded in anger after Arnold had seemingly rejected her, giving the locket and the repaired picture back to Helga after the class had been captured by Lasombra. Having forgiven Arnold, Helga thanked Brainy by kissing him before rushing off much to his surprise and delight. Helga's locket would later play a key role in releasing the cure that cured Arnold's parents and the Green Eyes, which would not have been possible had Brainy not retrieved it for Helga.
• Nadine – A young entomologist and Rhonda's best friend. She tends to find a lot of Rhonda's more stuck-up opinions ridiculous. In the episode "Dinner for Four", she sets cockroaches free in a restaurant as a favour for Helga. This is the only episode where she has a bigger role than Rhonda, for her usual role is Rhonda's satellite character. In "Parents Day", Nadine is shown to be half black and half white on her mother and father's side respectively.
• Park – A close friend of Arnold and others. In the episode "Longest Monday", it is revealed that he has a secret hideout at the local junkyard. He only speaks in seasons 1–3.
• Joey Stevenson – An African-American boy who is easy to remember by knowing he is missing a tooth. He appears with Arnold's group of friends from time to time, though his most prominent roles are in the first season, when he was part of Harold's circle of friends, along with Iggy, Stinky, and Sid.
• Peapod Kid – A wealthy and well-spoken fourth grade student. In "Downtown as Fruits" he was unnamed but was credited as "Peapod Kid" because his costume for the school play was a pea pod. The name stuck and in later episodes he is called Peapod or Peapod Kid by the other children.
• "Chocolate Boy" – A boy obsessed with chocolate. In "Chocolate Boy", it is revealed he eats chocolate because his nanny fed him large amounts of chocolate before she left to a "far away land called Delaware." Arnold helps break Chocolate Boy of his obsession, but he only becomes as equally over-excessive eating radishes as a replacement.
• Wolfgang – The main bully of the block who is a fifth grader and Arnold's arch-enemy. He is more of a bully than Helga, also runs the fifth grade, and leads the other fifth-grade bullies in their troublemaking against younger students. Similar to Arnold, Wolfgang is somewhat popular with many friends in his grade, aside from his mildly dimwitted right-hand man, Edmund. The character, introduced during the second season, was created as a way for Caudell to stay on the show, as he was going through puberty and he could no longer voice Arnold as a result.
• * Edmund – Wolfgang's best friend and sidekick. He often asks stupid questions, causing Wolfgang to remark "Shut up, Edmund."
• * Mickey – A fifth grader who is nicknamed "The Weasel" as seen in "Longest Monday."
• Gloria – A girl who looks like Helga, but is more girly and has a nicer personality. Her first appearance is in "Magic Show" as a dream vision, but she is revealed to be a reality in "Helga's Boyfriend" when Stinky begins dating her, and appears as an extra in "Cool Party".
• Ludwig – A bully who only appears in the episode "New Bully on the Block", where after leaving juvenile hall, he, Arnold, and Wolfgang fight each other for control over Gerald Field. But at the end of the episode, Ludwig and Wolfgang become friends and attack Arnold and his friends, leaving them hanging on a football goal post well into the night. He never appeared again afterwards. His name is likely a reference to Ludwig Van Beethoven, a famous classical composer, as a counterpoint to Wolfgang who shares his first name with classical composer Wolfgang Amadeus Mozart, and similar to Wolfgang, was created so that there would be an episode featuring Arnold's then-current voice actor amongst his previous voice actors.
• Ruth P. McDougal – A sixth-grade girl who was Arnold's first crush. Arnold went on a date with her on Valentine's Day but realized that she was not very nice after he caught her red-handed with the waiter at the restaurant and left with him. In the episode "What's Opera Arnold?" She played the role of Carmen and Arnold played the role of Don José from the opera Carmen. But was interrupted by Helga who slingshot Ruth into a trap door on stage in the middle of the kissing scene.
• Connie and Maria – Two sixth-grade girls, Maria is a Latina, who speaks with a Mexican accent, often using Spanish words in discussion. They ask Arnold and Gerald to be their dates in the episode " Sixth Grade Girls" although just to use them to make their boyfriends jealous, but both agree that they are sweet and have potential to attract their interest in the future, when they are older than fourth graders. The two often appear in later episodes when the sixth grade classroom is shown, either with or without dialogue. In the episode "Pheobe Skips" They and along with their two other friends Cookie and Symone tricked Pheobe into doing their homework for them while they watched a soap opera. Near at the end of the episode there was a new girl named Shavone who got transferred from the third grade to their sixth grade class. They told Pheobe that they no longer needed her services and planned on making Shavone their new homework girl.
• Patricia "Big Patty" Smith – An ill-tempered sixth-grade girl who becomes Harold's friend. She dislikes Helga because of her pranks and was a bully like her. In an earlier episode, she plans to fight Helga, but stages it instead. She even asks Helga if she and Arnold had feelings for each other, which Helga denies. In season 4, she becomes friends with Rhonda after they both attend the same finishing school together. She was also held back a couple of years and is 14-years-old.
• * Mrs. Smith – Mother of Patty who possess the medical condition of dwarfism.
• * Mr. Smith – Father of Patty who also possesses the medical condition of dwarfism.

  Staff of PS 118

• Superintendent Chaplin – An official who supervises schools in the city as seen in "Principal Simmons".
• Principal Wartz – The strict, yet open-hearted principal of the school. In the episode "Full Moon" Harold, Stinky and Sid mooned him and Principal Wartz didn't see their faces he saw Arnold first and accused him for mooning. Principal Wartz gaved Arnold four weeks detention for not telling him who really did mooned him. Principal Wartz tells Arnold about how his friends put a frog in their teacher's desk. His friends got in big trouble with the teacher and she gaved Principal Wartz a gold star for telling the truth which caused him to be beaten up by his friends and they called him a "Weasle" he didn't even go on a date until he was 23-years-old. Frustrated and impatient, Principal Wartz told Arnold that he was gonna check off the failure to cooperate box on his permanent record. Harold, Stinky and Sid come clean and broke down crying and Principal Wartz lets Arnold off the hook. In the episode "Suspended" he suspends Wolfgang for misusing the fire extinguisher. Harold decided to get himself suspended so he can get a break from school he calls Principal Wartz a "Stupid Dork" which has him suspended for a week. With his friends in school and nobody to hang out with, Harold comes up with crazy schemes to get back in school but was thwarted by Principal Wartz. Arnold tries to talk some sense into him but Principal Wartz suspenses him for two days. Arnold and Harold decided to copy the schools regulations but tells him that they have the old policy. Harold broke down crying and begging for forgiveness Principal Wartz accepts his apology and allows him back in school on the condition that he catches up on the work he missed and he also lifts Arnold's suspension.
• Dr. Bliss – A child psychologist who evaluates the students of P.S. 118 for a day and later becomes Helga's psychoanalyst. She is also the second known character that is told by Helga that she loves Arnold. This character only appeared in one episode titled "Helga on the Couch." She became a background character in '.
• Miss Felter – A substitute teacher who was one of Arnold's "crushes." This character only appeared in the episode "Crush on Teacher." In the episode Gerald overheard her talking in the teacher's lounge that she was gonna have dinner with Arnold but it was her fiance who has the same name as him.
• Mr. Frank – A sixth-grade teacher, who is quite bored with his job.
• Lieutenant Major Goose – Arnold's teacher for a short time, a martinet. He also was Martin Johanssen's drill sergeant during the Vietnam War as seen in flashbacks in the "Veterans Day" episode.
• Lunch Lady – A woman in charge of the school cafeteria. She is stereotypically brash in appearance, but sensitive to criticism of the cafeteria food.
• Mr. Packenham – A fifth grade teacher. He appears in "What's Opera, Arnold?" when he chaperones Arnold's class trip to the Opera and in "Back to School" when Arnold's grandpa returns to school for a grade school diploma while in fifth grade, during his rapid progress from fourth through to sixth grade.
• Miss Slovak – Arnold's enthusiastic teacher. She leaves teaching to pursue a career in golf.
• Mr. Robert Simmons – Arnold's sensitive and caring teacher. He replaced Miss Slovak. He emphasizes the unique value of every individual in his class, with his constant reminding that "you are all special in your own special way". In the episode "Principal Simmons" he becomes principal at P.S.118 but then when the entire student body started rebelling against him, he and Arnold went to Principal Wartz's house and begged him to come back to the school but also made him promised to not be so tough on the students. Mr. Simmons then went back to being a teacher. In The Jungle Movie he became Arnold's fifth grade teacher and he chaperoned his students on the class trip to San Lorenzo. In 2018, Bartlett confirmed that Mr. Simmons was gay, which had been alluded to in the episode "Arnold's Thanksgiving" with the appearance of his partner, Peter.
• Nurse Shelly – The school nurse, and Sheena's Aunt. She had some speaking parts in some episodes. In the episode "Rhonda's Glasses" she gave Rhonda an eye test and helped her with her motion sickness. In the episode "April Fools Day" she helped Helga with her temporary blindness.
• Coach Jack Wittenberg, the competitive school coach of many sports teams, which he often gets Arnold and his friends to join. He is portrayed as an aggressive and incompetent coach, and as such, is unable to motivate and guide his team properly. With Arnold's help, he is able to lead his team to victory, as in the episode "Synchronized Swimming", and is revealed to have a sensitive and considerate side. He has a poor sense of vocabulary, as he often mispronounces words while confidently verbose. In the episode "Best Man" he asks Arnold to be the best man in his wedding and also had Gerald, Sid and Stinky as his groomsmen.
• * Tish Wittenberg – Jack's wife who is the coach of the girls' teams. She and Jack often compete with one another. In the episode "Best Man" she asks Helga to be her maid of honor in her wedding.
• * Tucker Wittenberg' – Jack's son who is a student of PS 118. In the episode Benchwarmer, his dad kept putting him in the game even though he did not think it was fair to his teammates until he stood up to his dad after he benched Arnold and his dad apologized to Tucker and Arnold for his actions. He and his parents made a cameo in The Jungle Movie''.

  Various

• Rex Smythe-Higgins – Grandpa's nemesis from when he was a child, of an esteemed British family, and often shown to have cheated against him in the past
• * Rex Smythe-Higgins III – His grandson, and similarly a rival to Arnold. However, unlike their grandfathers, the two have a respect for each other as they shook hands following Arnold winning a boat race which Rex refused to cheat in, and Rex even siding and helping Arnold rescue his pig Abner when his grandfather wanted to eat him.
• Dino Spumoni – A famous jazz singer based on Dean Martin and Frank Sinatra. In the episode "School Dance" he performs at Arnold's school dance but sings a very depressing song which causes Arnold's friends to get angry with him and after having a heart to heart conversation with Arnold in the dressing room he changes his tune by singing an upbeat song and having everyone dancing in the cafeteria where the dance was being held in. In the episode "Dino Checks Out" he fakes his death to have his record sales improve. Later in the episode it is revealed that he lived in Arnold's grandparents boarding house where he use to work as a construction worker and use to perform at night. Later in the episode it is revealed that Dino wears a toupee on his head and had multiple marriages. He's Italian American.
• Don Reynolds – Dino Spumoni's estranged, bitter partner and songwriter.
• Mr. Bailey – A worker of the Hall of Records. His first appearance is in the Christmas special, where Arnold comes to him to help find Mr. Hyunh's daughter, Mai. His second appearance is in the series' feature film, where he helps in trying to find the document of the "Tomato Incident". When he cannot find it, he tells Arnold about a man who keeps all kinds of historic records.
• Mayor Dixie – The female mayor of Hillwood. In ', she allows Scheck to redevelop Arnold's neighborhood, even though the city council rejected the idea. When she is shown Scheck destroying the document of the "Tomato Incident", she decides to make it a historic landmark once again.
• Mrs. Vitello – The owner of the neighborhood flower shop. In the episode "Part-Time Friends" She slipped on the floor of her flower shop and hurt her back but then Arnold and Gerald offered to run the flower shop for her while she rested her back.
• Councilman Marty Green – a dedicated butcher and a politician who works at Green Meats. He has two brothers, Dave and Benji, and a son who is a vegetarian. In the episode "Harold the Butcher" Harold steals a ham from his butcher shop and reluctantly has Harold work for him everyday after school for a week until he paid back the ham he tried to steal.
• Earl – He runs a passenger ferrying service across the lake to Elk Island, in a row boat. Despite his profession, he reveals that he cannot swim in the episode "Busses Bikes and Subways" He speaks with a suitable pirate accent, given his job, as well as other pirate stereotypes. He is also Sheena's uncle.
• Davy Jones – Former member of The Monkees. He and his band were shown at the end of the episode "Fishing Trip". When he told the audience that the band will take requests Harold asked him if he knew "Miss Susie Had A Tugboat" and they performed it on stage.
• Mickey Kaline – A retired baseball star and Arnold's favorite player. Arnold caught his final home run ball. After retirement he ran his own baseball-themed restaurant, Mickey's Dog Pound. He is based on two famous baseball players, Mickey Mantle and Al Kaline.
• Jimmy Kafka – Phil's best friend when they were young kids. Phil often mentions him when he tells Arnold stories of his past exploits. They both have had a bittersweet relationship, based on many disagreements involving competitions and other activities, however deep down they are very close, despite possible continuity errors following season 1's "Part Time Friends" episode in which it is said that he has not spoken to him since falling out working together.
• Rabbi Goldberg – A rabbi who gives Harold advice and guidance. In "Harold the Butcher", Rabbi Goldberg teaches Harold that stealing is wrong and he told Harold a story about when he was Harold's age that his friend stole a vest from a tailor's shop and was punished and had to work in the tailor's shop to see how much work it took to make a vest, and in "Harold's Bar Mitzvah", Goldberg helps Harold prepare for his Bar Mitzvah.
• Alphonse Perrier du von Scheck – A greedy developer who plans to tear down the neighborhood so he can build a mall, but is thwarted by Arnold, Helga, and Gerald.
• Lasombra – A Central American treasure hunter and pirate who endeavors to steal a relic called the Corazon from the Green Eyed People. He disguised himself as Eduardo to trick Arnold and the others into luring him to find his parents and help the Green Eyed People. Near the end of The Jungle Movie he falls off a cliff to his death, after a scuffle with Arnold, Helga, Gerald and Eduardo.
• * Che – A henchman of Lasombra. Helga's older sister Olga develops a crush on him before it's revealed that he works for Lasombra. Later in the movie when Arnold's grandparents and The Patakis come to San Lorenzo and rescue the others and after hearing that Che was mean to her, Big Bob starts chasing Che and beating him up for breaking Olga's heart.
• * Paulo – A henchman of Lasombra.
• Nick Vermicelli – One of Big Bob's business associates, and later an accomplice of Scheck.
• Big Gino – The school's mafia boss and loan shark, who is often shown victimizing students, particularly Sid in "Big Gino" with harassment and threats, when they fail to pay back on time what is loaned. Though often seen in or around P.S 118, he attends P.S 119. Despite his name, due to the irony of his small stature, it is his nickname.
• Stoop Kid – A teenage boy who lives on a stoop and never leaves it until episode "Stoop Kid", when Arnold coaxes Stoop Kid to finally have the courage to leave his stoop. The only other times Stoop Kid is seen off of his stoop are in the episodes "Arnold Betrays Iggy", where Stoop Kid is seen in the crowd of people near the end of the episode, "Eugene, Eugene!", when he is seen in the audience during the school's musical, and "Cool Party" when he was a guest at Arnold's 'geek' party.
• Campfire Lass – A young girl who is the head of a junior survivor skills based troop, called the Campfire Lads. She speaks with a Scottish accent, though Arnold thinks it is fake, and is often seen selling various goods to raise money for outings, or visits.
• Willie the Jolly Olly Man – The local ice cream man who is most often referred to as the "Jolly Olly Man," Willie is the driver of an ice cream truck that is frequently seen driving around Arnold's town. Throughout the series, he has been depicted as unfriendly, deranged, depressed, and hated by his employer until "Career Day" when Arnold helped him learn to adapt to the ways of his job and be nice to the children. On at least two occasions in later episodes however, he continues to reveal crazy tendencies. In one episode, he was the umpire at a baseball game Arnold and his friends played against the fifth graders.
• Eduardo – Eduardo is an anthropologist from a fictional Central American Republic of San Lorenzo. He was friends with Arnold's parents, Miles and Stella, and helped them during their expeditions in San Lorenzo. He is the last person to ever talk to Arnold's parents before they disappeared into the dense jungle.
• Harvey – The mailman who delivers mail and seems to occasionally give advice. He dislikes snow. In the episode "Gerald's Tonsills" he cheered Gerald up by telling him the story about his changing voice when he was about to sing in a school concert.
• Marty Green - The hard-working but good-natured butcher who runs Green Meats.
• Morrie and Vic''' – a duo often involved in criminal schemes. They set up a counterfeit penny operation in "Wheezin' Ed", work at an auto shop in "Grandpa's Packard", and are also seen as Oskar's friends in various episodes such as "Arnold as Cupid" and "Baby Oskar", frequently seen playing poker with him.

  Animals

• Abner – Arnold's pet pig. He was a wedding gift from the Green-eyed People to Miles and Stella from a water basket. Phil wanted to cook Abner but Stella decided to keep the pig as a pet. Abner was mistaken for a girl by Stella, who wanted to name "her" Isabelle. In The Jungle Movie he stowaways in Arnold's backpack on the trip to San Lorenzo. When Arnold, Abner and Gerald get to Eduardo's house they noticed that it was trashed and Abner sensed that something was wrong. When Arnold and the others got kidnapped by Lasombra and his crew, Abner swims to shore and catches an airplane back to Hillwood and tells Phil and Gertrude that Arnold and his friends got kidnapped by Lasombra and were in trouble.