Leo Gorcey
— Muggs McGinnis
Bobby Jordan
— Danny Breslin
Huntz Hall
— Limpy
Warren Hull
— Officer Tom Brady
Charlotte Henry
— Mary Breslin
Keye Luke
— Clancy
Bobby Stone
— Monk Martin
Donald Haines
— Skinny, red-haired kid
Sunshine Sammy Morrison
— Scruno
David Gorcey
— PeeWee
Martha Wentworth
— Mrs. Brady
Jack Mulhall
— Cop at Prizefight with the Lieutenant
Eddie Foster
— Slats Morrison
Dennis Moore
— Dorgan
Tony Carson
— Henchman Dutch
Pat Costello
— Muggs' Trainer
Dick Ryan
— Police Lieutenant
Bill Cartledge
— Johnny Ryan, Muggs' opponent (uncredited)
Minerva Urecal
— Head of Reform School (uncredited)
Jack Chefe
— Henchman Nick (uncredited)
Jack Carr
— Milkman George (uncredited)