Kim So-hye participated in the first season of Mnet’s reality show Produce 101 in 2016, where she finished in fifth place. This earned her a spot in the show’s project girl group I.O.I, which debuted in May 2016 with the EP Chrysalis. They officially disbanded in January 2017. That same year, she made her acting debut in the web series Poetry Story. In 2019, she played the female lead in the MBN and Dramax series Best Chicken. Also in 2019, she was cast in her first film role as Kim Hee-ae’s daughter in Moonlit Winter. Her performance in the movie gave her several Best New Actress wins and nominations. In 2020, she starred in the KBS2 short series How to Buy a Friend. In 2023, she joined Lee Sang-yub in the KBS2 sports drama My Lovely Boxer.

Kim So-hye played volleyball in junior high school. She enrolled at Sejong University’s film and arts department.