Lee Ha-na first appeared in a commercial for telecom KTF's "umbrella service" in 2005. A year later, she made a memorable acting debut in the critically acclaimed television dramaAlone in Love, as the extremely odd younger sister of the female protagonist. She played another supporting role as a small-time swindler in When Spring Comes in 2007. Later that year, Lee was cast in her first leading role in Merry Mary, a quirky romance between a mediocre singer and a failed novelist. This was followed by her big screen debut in Le Grand Chef, a film adaptation of Huh Young-man's manhwaSikgaek, in which Lee played a TV producer who teams up with an aspiring chef. Unlike her previous cheerful roles, Lee surprised critics and audiences in 2008 when she played a darker character in Women of the Sun. In the melodrama, her character wreaks revenge when she learns that her older adopted sister abandoned her at a train station out of jealousy, causing her to grow up impoverished in an orphanage. Lee won an Excellence Award at the year-end KBS Drama Awards. From November 21, 2008 to April 17, 2009, she was the host/MC of the live music program Lee Ha-na's Peppermint. Before she turned to acting, Lee had early aspirations of becoming a singer, so aside from introducing and interviewing guests, she frequently performed on the show, sometimes accompanying herself on the guitar or piano. Lee then underwent training for her role as a figure skating coach in Triple, who finds herself in a love triangle with her ex-husband and his best friend who pursues her. This led to her doing the narration for Queen Yuna! I am Korea, a TV documentary on Olympic-winning figure skater Yuna Kim, that aired on MBC. Lee was also the narrator for Dance of Time, a documentary film directed by Song Il-gon about the Korean diaspora in Cuba. In 2010, Lee was cast opposite veteran actor Ahn Sung-ki in Shin Yeon-shick's film The Fair Love. She played a twentysomething college student who after her father's death, embarks on an awkward yet endearing love affair with his friend, a bachelor in his fifties. This was followed in 2012 by the aviation action film , a remake of Shin Sang-ok's 1964 filmRed Scarf. After a five-year absence from the small screen, Lee returned in High School King of Savvy, a 2014 cable romantic comedy about a high school student who masquerades as an executive at his brother's IT company; she played a temp who shows him the ropes. In 2015, Lee was cast in the film Journalist, about the ruthless and at times unethical world of news reporting. In the same year, she also starred in KBS2's drama Unkind Ladies, which marked her 3rd time collaboration with screenwriter Kim In-young, after 2007s Merry Mary and 2008s Women of the Sun. In 2017, Lee starred in OCN's drama Voice as a policewoman with an enhanced sense of hearing. The drama was a hit, and its ratings broke existing OCN viewership records when it aired in Korea. She then filmed comedy filmSummer Vacation. In 2018, Lee left L&Company and signed with new management agency Saram Entertainment. Lee reprised her lead female role in Voice 2, the sequel to OCN's drama Voice. Despite the shorter run, Voice 2 surpassed the first season's ratings and eventually became the highest-rated OCN drama. That same year, Lee was appointed as an honorary member of the police force by South Korea's National Police Agency. In 2019, Lee once again reprised her lead female role in Voice 3, making her the lead on all three seasons of the Voice series. In 2020, Lee starred in the melodrama A Piece of Your Mind.
