Song Ji-hyo started out as a model before making her big screen debut in the 2003 horror film Whispering Corridors 3: Wishing Stairs, which earned her a Best New Actress nomination at the 24th Blue Dragon Film Awards. In 2006, she landed a main role in the MBC romantic comedy Goong, which became a hit across Asia. That same year, she became part of the MBC sageuk Jumong, in which she scored a Best New Actress for TV nomination at the 43rd Baeksang Arts Awards. The drama also took home the Daesang at the ceremony. In 2009, she bagged a nomination for Most Popular Actress for Film at the 45th Baeksang Arts Awards for her work in the erotic historical movie A Frozen Flower. In 2010, she joined the SBS variety show Running Man, which scored her numerous recognitions and further boosted her popularity. In 2014, she led the tvN series Emergency Couple, opposite Choi Jin-hyuk. In 2018, she starred in the KBS2 drama Lovely Horribly, in which she was nominated for an Excellence Award at the KBS Drama Awards.

Song Ji-hyo revealed in an episode of Running Man that she had changed her birth name to Chun Soo-yeon. Her younger brother named Chun Sung-moon debuted as an actor in 2017. Her mother was a competitive swimmer.