Gil Hae-yeon began her acting career on stage before making her screen debut in the 2003 omnibus film If You Were Me. She then became part of the 2005 movie Mapado and its 2007 sequel Mapado 2. She also appeared in the award-winning films Breathless in 2008 and Pluto in 2013. In 2015, she starred in the Canadian-Korean movie In Her Place, which won her Best Supporting Actress at the 3rd Wildflower Film Awards. It also gave her a Best Supporting Actress nomination at the 3rd Canadian Screen Awards. In 2015, she joined several TV series such as KBS2’s Heard It Through the Grapevine and Assembly, which earned her another Best Supporting Actress trophy at the 4th APAN Star Awards. In 2018, she played Sohn Ye-jin’s mother in the popular JTBC romance drama Pretty Noona Who Buys Me Food. In 2021, she acted alongside Shin Ha-kyun and Yeo Jin-gu in JTBC’s Beyond Evil, which was selected as Best Drama at the 57th Baeksang Arts Awards. That same year, she was cast in the Netflix original series The Silent Sea.

Gil Hae-yeon studied Korean language and literature at Dongduk Women’s University.