Bill Murray

Character: Garfield (voice)

Breckin Meyer

Character: Jon

Jennifer Love Hewitt

Character: Liz

Stephen Tobolowsky

Character: Happy Chapman

Evan Arnold

Character: Wendell

Mark Christopher Lawrence

Character: Christopher Mello

Jimmy Kimmel

Character: Spanky (voice)

Debra Messing

Character: Arlene (voice)

Nick Cannon

Character: Louis (voice)

Alan Cumming

Character: Persnikitty (voice)

Brad Garrett

Character: Luca (voice)

David Eigenberg

Character: Nermal (voice)

Jerry Hauck

Character: Cop

Richard Kind

Character: Dad Rat (voice)

Vanessa Campbell

Character: Miss Ace Hardware

Daamen J. Krall

Character: Announcer

Alyson Stoner

Character: Kid Rat (voice)

Rufus Gifford

Character: Dog Owner #1

Randee Reicher

Character: Dog Owner #2

Eve Brent

Character: Mrs. Baker

Bill Hoag

Character: Roy the Lodge Member

Susan Moore

Character: Dog Owner #4

Ben Kronen

Character: Older Man

Michael Monks

Character: Deputy Hopkins

Mel Rodriguez

Character: Security Officer

Ryan McKasson

Character: Dog Owner #3

Juliette Goglia

Character: Little Girl

Joseph Edward Taylor

Character: Frank

Crystal the Monkey

Character: Pet Monkey (uncredited)