Nathanial G. Rand
— Peter Grimsby
Charlie Carrick
— Narrator
Owen Maggs
— Young Peter
Billy Cochrane
— Younger Brother
Kaia Poole
— Susie Meyers
MaryBeth Hall
— Grandmother
Henry Hodson
— Nephew
Penny Corbett
— The One Who Got Away
Katye Seip
— Laughing Girl #1
Arielle Salama
— Laughing Girl #2
Jordan Canning
— Laughing Girl #3