The season follows the club competing on the show choir circuit, while its members, faculty and alumni deal with sex, bulimia, gender identity, child molestation, dyslexia, school violence, pregnancy scares and other social issues.

As of the season premiere, fourteen main cast members retained that status from the third season: glee club director Will Schuester (Matthew Morrison), cheerleading coach Sue Sylvester (Jane Lynch), glee club members Artie Abrams (Kevin McHale), Blaine Anderson (Darren Criss), Tina Cohen-Chang (Jenna Ushkowitz), and Brittany Pierce (Heather Morris), and graduates Rachel Berry (Lea Michele), Mike Chang (Harry Shum Jr.), Finn Hudson (Cory Monteith), Kurt Hummel (Chris Colfer), Mercedes Jones (Amber Riley), Santana Lopez (Naya Rivera) and Noah "Puck" Puckerman (Mark Salling).

Previously recurring character Sam Evans (Chord Overstreet), a glee club member, was promoted to the main cast in the fourth season.

[4] Agron and Jayma Mays, who continued to appear as guidance counselor Emma Pillsbury, were credited as guest stars this season rather than as series regulars.

Rachel psyches herself up for what she believes will be the most important audition of her life: a chance to play "Fanny Brice" in an all-new Broadway production of Funny Girl.

The fourth season continued with McKinley High in Lima, Ohio as the primary setting, while also following several of the just-graduated characters to New York City and the fictional performing arts school (NYADA).

Season 4 featured a teaming up of Coach Roz (NeNe Leakes) and Sue (Jane Lynch) to take down Principal Figgins (Iqbal Theba).

[44] 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, Cory Monteith, Amber Riley, Naya Rivera, Mark Salling and Harry Shum Jr. as McKinley graduates and former glee club members Kurt Hummel, Rachel Berry, Finn Hudson, Mercedes Jones, Santana Lopez, Noah "Puck" Puckerman and Mike Chang respectively; and Darren Criss, Kevin McHale, Heather Morris, Chord Overstreet and Jenna Ushkowitz as current glee club members Blaine Anderson, Artie Abrams, Brittany Pierce, Sam Evans, and Tina Cohen-Chang respectively.

Dean Geyer as Brody Weston, a handsome junior at Rachel's new school, Jacob Artist as McKinley sophomore Jake Puckerman, Puck's (Mark Salling) younger half brother, Becca Tobin as Kitty, a cheerleader, and Melissa Benoist as Marley Rose.

[58] Actress Whoopi Goldberg reprised her Season 3 role, Carmen Tibideaux, Dean of Vocal Performance and Song Interpretation at NYADA.

[59] Other recurring guests who returned include Vanessa Lengies as Sugar Motta, Samuel Larsen as Joe Hart and Alex Newell as Wade "Unique" Adams.

[61] Damian McGinty (Rory Flanagan) was not a part of the regular cast, but he made a special appearance in "Glee, Actually" as Artie's guardian angel in a dream sequence.

Grant Gustin returned as Dalton Academy Warbler Sebastian Smythe, and the group's new leader, Hunter, was played by Nolan Gerard Funk.

[65] Idina Menzel also reprised her role as Shelby Corcoran for a guest appearance in "Sweet Dreams" for the first time since her multi-episode arc in Season 3.