Lee Shi-young debuted as an actress in 2008 with appearances in the third season of Super Action TV’s Urban Legends Deja Vu and KBS2’s Kingdom of Wind. In 2010, she joined the main cast of the KBS2 series The Birth of the Rich, which won her Best New Actress at the KBS Drama Awards. In 2013, she acted alongside Oh Jung-se in the romantic comedy film How to Use Guys with Secret Tips, which earned her a Best Actress nomination at the 22nd Buil Film Awards. In 2017 and 2018, she bagged back-to-back Top Excellence Award nominations at the MBC Drama Awards for her performance in Lookout and Risky Romance. In 2019, she took home an Excellence Award at the KBS Drama Awards for the family drama What’s Wrong Mr. Poong-sang. In 2020, she starred in the Netflix apocalyptic horror series Sweet Home, which gave her Best Actress nominations at the 2021 Asian Academy Creative Awards and the 2021 Asia Contents Awards.

Aside from acting, Lee Shi-young also ventured into boxing. She picked up the sport in 2010 and competed in numerous amateur bouts. In 2013, she made it to the South Korean women’s national team after winning the 48-kilogram class at the 24th National Amateur Boxing Championships. She retired from the sport in September 2015 due to injuries.

Lee Shi-young married a restaurant entrepreneur named Jo Seung-hyun in September 2017. She gave birth to a son in January 2018.