Ryan Reynolds
Jerry Hickfang / Mr. Whiskers (voice) / Bosco (voice) / Deer (voice) / Bunny Monkey (voice)
Gemma Arterton
Fiona
Anna Kendrick
Lisa
Jacki Weaver
Dr. Warren
Ella Smith
Alison
Paul Chahidi
Dennis Kowalski
Stanley Townsend
Sheriff Weinbacher
Adi Shankar
John
Sam Spruell
Dave
Valerie Koch
Jerry's Mother
Gulliver McGrath
Jerry (12 years old)
Paul Brightwell
Jerry's Stepfather
Alessa Kordeck
Sheryl
Michael Pink
Jesus
Ricardia Bramley
Sheila Hammer
Alex Tondowski
Tom