The central characters are glee club director Will Schuester (Matthew Morrison), cheerleading coach and school principal Sue Sylvester (Jane Lynch), glee club members Artie Abrams (Kevin McHale), Blaine Anderson (Darren Criss), Tina Cohen-Chang (Jenna Ushkowitz), Sam Evans (Chord Overstreet) and graduates Rachel Berry (Lea Michele), Kurt Hummel (Chris Colfer), and Santana Lopez (Naya Rivera).

Previously recurring characters Jake Puckerman (Jacob Artist), Marley Rose (Melissa Benoist), Ryder Lynn (Blake Jenner), Wade "Unique" Adams (Alex Newell), and Kitty Wilde (Becca Tobin), who are current glee club members at WMHS, have been promoted to the main cast in the fifth season—though none of them appear in the last trimester, seven episodes, of the season, as the season moves its focus to the alumni.

Heather Morris, Amber Riley, Mark Salling, and Harry Shum, Jr., who have portrayed Brittany Pierce, Mercedes Jones, Noah "Puck" Puckerman and Mike Chang (respectively) since season one, are no longer series regulars, but did appear as guest stars.

[28] On July 18, 2013, it was announced the show would go on a two-week hiatus while its writers and producers rewrote the storylines and figured out how to handle the death of Monteith's character, Finn Hudson.

[29] On July 19, 2013, the show announced through their Facebook page that the season would premiere September 26, one week after the original date, and filming would begin in early August.

[37] Fox credits fourteen main cast members for the season: Matthew Morrison as glee club director Will Schuester; Jane Lynch as cheerleading coach Sue Sylvester; Chris Colfer, Lea Michele and Naya Rivera as McKinley graduates and former glee club members Kurt Hummel, Rachel Berry and Santana Lopez, respectively; and Jacob Artist, Melissa Benoist, Darren Criss, Blake Jenner, Kevin McHale, Alex Newell, Chord Overstreet, Becca Tobin and Jenna Ushkowitz as current glee club members Jake Puckerman, Marley Rose, Blaine Anderson, Ryder Lynn, Artie Abrams, Wade "Unique" Adams, Sam Evans, Kitty Wilde and Tina Cohen-Chang, respectively.

[39] Five actors depart the main cast: Cory Monteith (Finn Hudson), who died on July 13, 2013; and Heather Morris (Brittany Pierce), Amber Riley (Mercedes Jones), Mark Salling (Noah "Puck" Puckerman) and Harry Shum, Jr. (Mike Chang).

Lea Michele tweeted on August 22, 2013, that her friend Phoebe Strole would be appearing on Glee during the season; her character, Penny Owen, was a sophomore in college and a new love interest for Sam Evans (Chord Overstreet).

The former included Ruby, a new African-American student at McKinley High, and two women in their twenties, Ryan, who sings and plays the guitar, and a "cute and quirky" character variously named Julie and Jenny, who will first appear in the second episode.

[65] The four males include three men in their forties or fifties: the talented and egotistical Roderick Easton; an intelligent and good-looking teacher named Jim Elliott; and Jurgen, who speaks with an Austrian or German accent.

[67] A character who would end up fitting the description of a man with a German or Austrian accent in his forties or fifties is Gunther (Christopher Curry), who runs the Spotlight Diner.