Yoon So-yi got her start in the entertainment industry as a commercial model before debuting as an actress in 2004 with a starring role in director Ryu Seung-wan’s action film Arahan. Her work in the movie scored her Best New Actress nominations at the 41st Grand Bell Awards and the 25th Blue Dragon Film Awards. That same year, she starred in the MBC series Say You Love Me, which gave her a Best New Actress nomination at the MBC Drama Awards. In 2008, she acted alongside Lee Jin-wook and Kim Seung-soo in SBS’s City of Glass, which won her the New Star Award at the SBS Drama Awards. In 2009, she worked with Lee Jun-ki in the MBC action-comedy Hero. In 2011, she joined the main cast of the SBS fusion sageuk Warrior Baek Dong-soo, which earned her an Excellence Award at the SBS Drama Awards. In 2014, she was nominated for another Excellence Award at the KBS Drama Awards for her leading role in the daily series Angel’s Revenge. In 2019, she was named Best Actress at the 27th Korea Culture and Entertainment Awards for the KBS2 daily drama A Place in the Sun.

Yoon So-yi married musical actor Jo Sung-yoon in 2017. In November 2021, she gave birth to a daughter.