John C. Reilly

Character: Dewey Cox

Jenna Fischer

Character: Darlene Madison

Raymond J. Barry

Character: Pa Cox

Kristen Wiig

Character: Edith

Tim Meadows

Character: Sam

Harold Ramis

Character: L'Chaim

Margo Martindale

Character: Ma Cox

Chris Parnell

Character: Theo

Matt Besser

Character: Dave

Nat Faxon

Character: Awards Show Stage Manager

Conner Rayburn

Character: Dewey Age 8

Chip Hormess

Character: Nate

Terrence Beasor

Character: Country Doctor

Honeyboy Edwards

Character: Old Bluesman

Gerry Black

Character: Harmonica Player

Aron Johnson

Character: Teenage Band

Jack Donovan Saperstein

Character: Teenage Band

Taylor Hubert

Character: Teenage Band

Christopher Hurt

Character: Teenage Band

Matt Price

Character: MC (Teacher)

John Maynard

Character: Man at Talent Show

E.J. Callahan

Character: Second Man at Talent Show

Rance Howard

Character: Preacher

Craig Robinson

Character: Bobby Shad

Paul Bates

Character: Nightclub Manager

Patrick Faucette

Character: Bad Men Bass Player

Phil Rosenthal

Character: Mazeltov

Martin Starr

Character: Schmendrick

Oscar Dillon

Character: Audience Guy at Nightclub

Jack McBrayer

Character: DJ

Molly C. Quinn

Character: Teen with Pinups

John Ennis

Character: The Big Bopper

Frankie Muniz

Character: Buddy Holly

Ed Helms

Character: Stage Manager

Jack White

Character: Elvis Presley

Angela Little

Character: Beth Anne

Odette Annable

Character: Reefer Girl

Tyler Nilson

Character: Bert

Deanna Brooks

Character: Hotel Groupie with Dewey

Ian Roberts

Character: Drug Dealer

Steve Bannos

Character: Prison Guard

Willow Geer

Character: Rehab Nurse

David Doty

Character: Rehab Doctor

Jack Kehler

Character: Press Conference Reporter

Gerry Bednob

Character: The Maharishi

David Krumholtz

Character: Schwartzberg

Tim Bagley

Character: Engineer

Jane Lynch

Character: Gail the Television Reporter

Skyler Gisondo

Character: Dewdrop

Kshitij Pendurkar

Character: Dewey Rahim

Simon Helberg

Character: Dreidel L'Chaim

Jacques Slade

Character: Lil' Nutzzak

Danica Rozelle

Character: Music Video Girl

Lurie Poston

Character: Cox Kid

Maggie Mannion

Character: Cox Kid

Jackson Browne

Character: Jackson Browne

Jewel

Character: Jewel

Lyle Lovett

Character: Lyle Lovett

Stacey Scowley

Character: Pierced Eyebrow Girl

Ajla Hodžić

Character: Pierced Lip Girl

Ghostface Killah

Character: Ghostface Killah

Otis Williams

Character: The Temptations

Ron Tyson

Character: The Temptations

Terry Weeks

Character: The Temptations

Joe Herndon

Character: The Temptations

Bruce Williamson

Character: The Temptations

Eddie Vedder

Character: Eddie Vedder

Jack Black

Character: Paul McCartney (uncredited)

Paul Rudd

Character: John Lennon (uncredited)

Justin Long

Character: George Harrison (uncredited)

Jason Schwartzman

Character: Ringo Starr (uncredited)

Patrick J. Adams

Character: The Kid (uncredited)

Clement Blake

Character: Edith's Father (uncredited)

Patrick Duffy

Character: Patrick Duffy (uncredited)

Morgan Fairchild

Character: Morgan Fairchild (uncredited)

Paul Feig

Character: Different DJ (uncredited)

Amber Hay

Character: LSD Vision (uncredited)

John Michael Higgins

Character: Record Producer (uncredited)

Jonah Hill

Character: Older Nate (uncredited)

Neil Ironfield

Character: Dewey's Child (uncredited)

Cheryl Ladd

Character: Cheryl Ladd (uncredited)

Cheryl Tiegs

Character: Cheryl Tiegs (uncredited)

Serria Tawan

Character: 70's African American Woman (uncredited)

Adam Herschman

Character: Jerry Garcia (uncredited)

John D. Crawford

Character: Officer Clark