He is known for his work in musical theatre on Broadway and for his role as Wes, a member of the Dalton Academy Warblers on the Fox comedy-drama series Glee.

[3] He gained admission into New York's prestigious Stuyvesant High School, from which he graduated in 1998,[4] alongside fellow actor Malcolm Barrett.

It was at Stuyvesant that Leung seriously pursued theater, performing in high school productions of Pippin, Guys & Dolls, and West Side Story.

He worked with directors and choreographers including Tony Award winner Thommie Walsh, Larry Fuller, and Lee Roy Reams.

It was also at CMU that he met fellow Broadway performer Billy Porter, who returned to his alma mater to direct the main stage production of Stephen Sondheim's Company.

In the fall of 2002, Leung made his Broadway debut in the revival of Flower Drum Song, starring Lea Salonga, as a member of the ensemble and an understudy for Wang Ta.

In October 2015, Leung returned to Broadway in the musical Allegiance at the Longacre Theatre alongside co-stars George Takei and Lea Salonga.