Jane Lynch recorded segments for the film as Sue Sylvester but the scenes were not used in the final cut. The scenes appear in the home video release.
After the song "Teenage Dream" finishes, you can catch a glimpse of Damian McGinty (from The Glee Project (2011)) in the audience.
The concert features a setlist of songs from the show's first and second seasons. However, not every song that was performed on the Glee Live Tour is on the album (such as "Friday" and "True Colors"). "Dog Days Are Over", "Single Ladies" and "Friday" did not appear in the film, but were included on the home release. The order that the tracks appear is also not the order in which the songs were performed.
Unlike most concert movies, this is partly a mockumentary as the actors are actually in character as their Glee personae even during the backstage scenes. According to director Kevin Tancharoen, if they were playing themselves the film would have been completely disconnected from what made the show popular as the characters mean something different to everybody else.
Glee club mentor Will Schuester (Matthew Morrison) wasn't part of the 'Glee Live! In Concert!' tour, presumably because he was busy with recording and promoting his solo album at the time.