Bill Murray as Garfield (voice)

Breckin Meyer as Jon

Jennifer Love Hewitt as Liz

Stephen Tobolowsky as Happy Chapman

Evan Arnold as Wendell

Mark Christopher Lawrence as Christopher Mello

Jimmy Kimmel as Spanky (voice)

Debra Messing as Arlene (voice)

Nick Cannon as Louis (voice)

Alan Cumming as Persnikitty (voice)

Brad Garrett as Luca (voice)

David Eigenberg as Nermal (voice)

Jerry Hauck as Cop

Richard Kind as Dad Rat (voice)

Vanessa Campbell as Miss Ace Hardware

Daamen J. Krall as Announcer

Alyson Stoner as Kid Rat (voice)

Rufus Gifford as Dog Owner #1

Randee Reicher as Dog Owner #2

Eve Brent as Mrs. Baker

Bill Hoag as Roy the Lodge Member

Susan Moore as Dog Owner #4

Ben Kronen as Older Man

Michael Monks as Deputy Hopkins

Mel Rodriguez as Security Officer

Ryan McKasson as Dog Owner #3

Juliette Goglia as Little Girl

Joseph Edward Taylor as Frank

Crystal the Monkey as Pet Monkey (uncredited)