Oh's first acting role of note came when she landed the lead in the 1993 Canadian telefilm The Diary of Evelyn Lau. The next year, Oh was introduced to U.S. audiences and scored kudos for her turn in the big-screen drama Double Happiness, following up with Last Night (1998), which earned her further acclaim. But it was her unforgettable performance as the scorned Stephanie in 2004's Sideways that brought Oh bona fide fame.
Oh has since become a familiar face on television with her portrayal of Dr. Cristina Yang on "Grey's Anatomy." For her work on the series, Oh won a 2006 Golden Globe Award and earned multiple Emmy nominations.