Kim Haneul started out as an apparel model before debuting as an actress in the 1998 film Bye June. The following year, she was nominated for Best New Actress at the 20th Blue Dragon Film Awards for the medical drama movie Doctor K. In 2001, she was launched into stardom after starring in the top-rating SBS series Piano. She then acted alongside Kim Jae-won in the 2002 MBC drama Romance, which won her a Top Excellence Award at the MBC Drama Awards. She further cemented her success with appearances in the hit romantic comedy films My Tutor Friend and Too Beautiful to Lie in 2003 and 2004. She was named Best Actress at the 40th Baeksang Arts Awards for her performance in the latter. In 2011, she won Best Actress at the 48th Grand Bell Awards and the 32nd Blue Dragon Film Awards for her role as a visually impaired woman in the crime thriller film Blind. In 2012, she headlined the SBS series A Gentleman’s Dignity, which gave her a Top Excellence Award at the SBS Drama Awards. In 2016, she received another Top Excellence Award at the KBS Drama Awards for the romantic melodrama On the Way to the Airport.
Kim Haneul attended the Seoul Institute of the Arts. She married a businessman in March 2016 after dating him for about a year. The couple welcomed their first child in May 2018.