Since 2008, Shum was given roles in Step Up 2 and later Step Up 3D, both directed by Jon M. Chu. From 2009 until 2015, he portrayed the role of Mike Chang, a dancer who joins the glee club, on the Fox musical comedy-drama series Glee. Known for a while as "Other Asian" on Glee, he was given very few lines during the show's first season. Partly due to the enthusiasm from fans during his appearances on the live tour taking place after the first season concluded, Shum's character was given storylines in the second season, mostly involving his relationship with fellow glee club member Tina Cohen-Chang (Jenna Ushkowitz). He subsequently gave performances of "Make 'Em Laugh" in "The Substitute", "Sing" from A Chorus Line in "Duets", "Valerie" in "Special Education", and the show's first dance solo in "A Night of Neglect". He was promoted from guest star to series regular for the third season. He was given a major storyline in the third episode of the season, "Asian F", and performed "Cool" from West Side Story, his first solo song. On June 28, 2013, it was reported that Shum would not return as regular on Glee's fifth season, but would be a recurring guest star.