He proceeded to guest star on popular shows such as Judging Amy and Close to Home. Gallner joined the cast of Veronica Mars as Cassidy Casablancas toward the end of the show's first season, in May 2005, before becoming a season regular during the show's second season. After playing Bart Allen in the Smallville episode "Run", Gallner reprised the role on the January 18, 2007, episode "Justice" and the season eight finale. He also guest starred on Cold Case as a teenaged gunman in the episode "Rampage", and appeared in the independent filmSublime. In 2007, he guest starred in an episode of titled "Impulsive" as a high school student who accuses his teacher of statutory rape. He also guest starred in an episode of Bones as Jeremy Farrell, the suspected murderer of a child beauty-pageant contestant. He also played the lead role in the horror filmThe Haunting in Connecticut, playing a cancer patient who is tormented by evil spirits. He appeared in the independent film Cherry, filmed on the campuses of Kalamazoo College and Western Michigan University, along with several locations in downtown Kalamazoo, Michigan. He plays Aaron, an Ivy-League freshman who falls for an older woman while becoming the object of affection for the woman's young daughter. Gallner played Quentin in the 2010 reboot of A Nightmare on Elm Street; his character is the love interest of main character Nancy. Gallner played the brother of Aaron Paul's character in the 2012 film, Smashed. Gallner played Zach in one episode in the fourth season of AMC's The Walking Dead. It was initially reported that he would be a recurring character, but his character was killed off, instead. In 2014, Gallner played the role of Kurt, the antagonist to lead character Sam, in the independent film Dear White People.
Personal life
Gallner's father is of Jewish descent. Gallner is good friends with actor Jake Abel, his former roommate. The two had a band called The Third Kind together for a short time. Gallner attended Abel's wedding to Allie Wood in late 2013, and Abel attended Gallner's wedding to Tara Kathryn on December 12, 2015. Gallner is also good friends with fellow actor Chris Coy. In 2013, Kyle co-founded the independent production company Minutehand Pictures along with Oliver Thompson and Bay Dariz. The trio is currently producing the feature film Welcome to Happiness, in which Gallner portrays Woody Ward, a children's-book author with a secret door in his closet. Gallner and his wife have two sons.
