Lee was born in San Diego, California, to immigrant parents from South Korea. As a young man, he was expected to run his family's clothing store. At the local community college, he was spotted by Frank Burns, manager of La Jolla's Comedy Store.

Lee officially joined the cast of MadTV in 2001 as a feature performer for the seventh season. He was promoted to a repertory performer status the following season, and has stayed there since.

Lee created many characters on the show, including Bae Sung, Hideki the "Average Asian" (an Asian American who is constantly being pestered by others who stereotype him based on his ethnicity), Tank Read more...

In June 2008, it was reported that Comedy Central had taken a new show from Lee to pilot on their network. The show, as yet untitled, is said to "see Lee explore cultures and race, initially looking at the "divide" between blacks and South Koreans."