Zac Efron
as Mike O'Donnell

Leslie Mann
as Scarlett O'Donnell

Thomas Lennon
as Ned Gold

Michelle Trachtenberg
as Maggie O'Donnell

Sterling Knight
as Alex O'Donnell

Matthew Perry
as Mike O'Donnell (Adult)

Tyler Steelman
as Ned Gold (Teen)

Allison Miller
as Scarlett (Teen)

Adam Gregory
as Dom

Hunter Parrish
as Stan

Mario Cassem
as Samir

Kat Graham
as Jamie

Tiya Sircar
as Samantha

Melissa Ordway
as Lauren

Melora Hardin
as Principal Jane Masterson

Brian Doyle-Murray
as Janitor

Josie Loren
as Nicole

Jim Gaffigan
as Coach Murphy

Randy Gordon
as Photographer

Collette Wolfe
as Wendy

Tommy Dewey
as Roger

Linda Miller
as Female Janitor

Lorna Scott
as Secretary

Kodi Kitchen
as Hostess

Ellis Williams
as Bailiff

Diana Maria Riva
as Judge

Jeff Snyder
as Waiter

Antonio Todd
as Referee (1989)

Angee Hughes
as Waitress

Ed Ackerman
as School Cop

Will Schaub
as Referee

Loren Lester
as Mike's Lawyer

Alexander George
as Kid in Hallway

Nicole Sullivan
as Naomi

Margaret Cho
as Mrs. Dell

Larry Poindexter
as Dean

Bubba Lewis
as Dorky Kid (Ned's Party)

Chris Valenti
as Syracuse Scout (1989)

G. Lane Hillman
as Kevin (1989)

Hope Riley
as Girl (Wyatt)

Jeanine Jackson
as Scarlet's Lawyer

Gregory Sporleder
as Ohio Scout

Keith Oney
as Guy in Crowd

Leonard Wu
as Kid (Office)

Liana Blackburn
as Cheerleader (1989)

Lindsay Taylor
as Cheerleader (1989)

Danielle E. Hawkins
as Cheerleader (1989)

Shelby Rabara
as Cheerleader (1989)

Katrina Norman
as Cheerleader (1989)

Tiana Brown Gandelman
as Cheerleader (1989)

Rhapsody Violetti
as Cheerleader (1989)

Taisha Monique Clark
as Cheerleader (1989)

Vanessa Lee Chester
as Cheerleader

Chanel Malvar
as Cheerleader

Tyne Stecklein
as Cheerleader

Galen Hooks
as Cheerleader

Kiara Ely
as Cheerleader

Mihran Kirakosian
as Cheerleader

Rachele Brooke Smith
as Hammer Dancer

Jesse Heiman
as Mascot

Dres Reid
as Cheerleader

Christopher Scott
as Hammer Dancer

Eric McCoy
as Hammer Dancer

Raymond Chacon
as Jazz

Megan Galiber
as Girl #2

Renée King
as ROTC Leader

Jordan Schatz
as Mr. Adams

Jaclyn Matfus
as Party Girl

Justin C. Todd
as Football Player

Keith Oney
as Guy in Crowd