Ken Leung was born on January 21, 1970 in New York City. He attended New York University on a scholarship and subsequently became interested in acting, later training with the likes of Catherine Russell and Nan Smithner. He also performed in street plays and small performance spaces. He made his film debut in 1995, in a minor role in the romantic independent film Pictures of Baby Jane Doe. He also made guest appearances in television shows such as New York Undercover and Law & Order before being cast in his first major role, in the 1998 action comedy film Rush Hour, where he plays the antagonist Thomas Griffin’s (Tom Wilkinson) right hand man Sang.
After appearing in other films such as Maze, The Family Man and Edward Norton’s directorial debut Keeping the Faith, he made a guest appearance in the HBO prison drama Oz. He also had minor roles in films such as A.I.: Artificial Intelligence, Spy Game and Vanilla Sky. In 2004, he was cast as Detective Steven Sing in the horror film Saw, but his character was killed off in the first movie. He then appeared in television shows like Whoopi and The Jury.
In 2006, Leung was cast in the film X-Men: The Last Stand, playing a character credited as Kid Omega, although he resembles the character Quill. He then made a guest appearance on The Sopranos, playing the intelligent Chinese-American patient Carter Chong, who suffers from a mental disorder and looks up to Junior Soprano (Dominic Chianese). He soon joined the cast of the ABC hit series Lost, as the hotheaded, sarcastic and hostile medium Miles Straume, who is part of the passengers of the freighter Kahana and kept prisoner in the island. The show’s producers cast him after his stint on The Sopranos, and wrote the character especially for him. In 2007, Leung got a role in the animated fantasy Year of the Fish, written and directed by David Kaplan. He was also seen on the romantic comedy Shanghai Kiss, enabling him to work with Hayden
Panettiere and Kelly Hu.