Park Shi-yeon began her career as a contestant in the Miss Korea pageant in 2000 before making her acting debut in China. In 2005, she landed her first starring role in the hit SBS romantic comedy My Girl, which won her the New Star Award at the 2006 SBS Drama Awards. Also in 2006, she starred in the musical comedy film The Fox Family, which earned her the Best New Actress for Film trophy at the 43rd Baeksang Arts Awards. In 2007, she headlined the action drama film A Love, opposite Joo Jin-mo. She was named Best New Actress at the 27th Korean Association of Film Critics Awards for her work in the movie. In 2010, she starred in the SBS series Coffee House, in which she was nominated for an Excellence Award at the SBS Drama Awards. In 2012, she acted alongside Song Joong-ki and Moon Chae-won in the KBS2 melodrama Nice Guy, which gave her an Excellence Award nomination at the KBS Drama Awards.

Pak Shi-yeon dated singer-actor Eric from 2004 to 2007. In November 2011, she married her non-celebrity boyfriend. They have two children together. In 2013, she was found guilty of propofol abuse and was given suspended jail terms. In 2016, she filed for divorce from her husband of five years.