Bae Hae-sun debuted as an actress in the play Gone with the Wind in 1995. In 2002, she won the Female Rookie Award at the 8th Korea Musical Awards for The Rehearsal. That same year, she made her big screen debut in director Choi Ho’s film Who Are You. In 2005, she was named Best Actress at the 11th Korea Musical Awards for Aida. In 2009, she took home the Best Supporting Actress trophy at the 3rd Daegu Musical Awards for Three Musketeers. In 2015, she landed her first television role in the SBS series Yong-pal, which earned her a Special Award nomination at the SBS Drama Awards. In 2016, she was once again nominated for a Special Award at the SBS Drama Awards for the romantic comedy series Jealousy Incarnate. She also played notable supporting roles in the 2019 tvN dark fantasy drama Hotel del Luna and the 2022 Netflix zombie series All of Us Are Dead.

Bae Hae-sun majored in theater at the Seoul Institute of the Arts.