John C. Reilly

Dewey Cox

Jenna Fischer

Darlene Madison

Raymond J. Barry

Pa Cox

Kristen Wiig

Edith

Tim Meadows

Sam

Harold Ramis

L'Chaim

Margo Martindale

Ma Cox

Chris Parnell

Theo

Matt Besser

Dave

Nat Faxon

Awards Show Stage Manager

Conner Rayburn

Dewey Age 8

Chip Hormess

Nate

Terrence Beasor

Country Doctor

Honeyboy Edwards

Old Bluesman

Gerry Black

Harmonica Player

Aron Johnson

Teenage Band

Jack Donovan Saperstein

Teenage Band

Taylor Hubert

Teenage Band

Christopher Hurt

Teenage Band

Matt Price

MC (Teacher)

John Maynard

Man at Talent Show

E.J. Callahan

Second Man at Talent Show

Rance Howard

Preacher

Craig Robinson

Bobby Shad

Paul Bates

Nightclub Manager

Patrick Faucette

Bad Men Bass Player

Phil Rosenthal

Mazeltov

Martin Starr

Schmendrick

Oscar Dillon

Audience Guy at Nightclub

Jack McBrayer

DJ

Molly C. Quinn

Teen with Pinups

John Ennis

The Big Bopper

Frankie Muniz

Buddy Holly

Ed Helms

Stage Manager

Jack White

Elvis Presley

Angela Little

Beth Anne

Odette Annable

Reefer Girl

Tyler Nilson

Bert

Deanna Brooks

Hotel Groupie with Dewey

Ian Roberts

Drug Dealer

Steve Bannos

Prison Guard

Willow Geer

Rehab Nurse

David Doty

Rehab Doctor

Jack Kehler

Press Conference Reporter

Gerry Bednob

The Maharishi

David Krumholtz

Schwartzberg

Tim Bagley

Engineer

Jane Lynch

Gail the Television Reporter

Skyler Gisondo

Dewdrop

Kshitij Pendurkar

Dewey Rahim

Simon Helberg

Dreidel L'Chaim

Jacques Slade

Lil' Nutzzak

Danica Rozelle

Music Video Girl

Lurie Poston

Cox Kid

Maggie Mannion

Cox Kid

Jackson Browne

Jackson Browne

Jewel

Jewel

Lyle Lovett

Lyle Lovett

Stacey Scowley

Pierced Eyebrow Girl

Ajla Hodžić

Pierced Lip Girl

Ghostface Killah

Ghostface Killah

Otis Williams

The Temptations

Ron Tyson

The Temptations

Terry Weeks

The Temptations

Joe Herndon

The Temptations

Bruce Williamson

The Temptations

Eddie Vedder

Eddie Vedder

Jack Black

Paul McCartney (uncredited)

Paul Rudd

John Lennon (uncredited)

Justin Long

George Harrison (uncredited)

Jason Schwartzman

Ringo Starr (uncredited)

Patrick J. Adams

The Kid (uncredited)

Clement Blake

Edith's Father (uncredited)

Patrick Duffy

Patrick Duffy (uncredited)

Morgan Fairchild

Morgan Fairchild (uncredited)

Paul Feig

Different DJ (uncredited)

Amber Hay

LSD Vision (uncredited)

John Michael Higgins

Record Producer (uncredited)

Jonah Hill

Older Nate (uncredited)

Neil Ironfield

Dewey's Child (uncredited)

Cheryl Ladd

Cheryl Ladd (uncredited)

Cheryl Tiegs

Cheryl Tiegs (uncredited)

Serria Tawan

70's African American Woman (uncredited)

Adam Herschman

Jerry Garcia (uncredited)

John D. Crawford

Officer Clark

Jayne Eastwood

70's Girl (uncredited)