Don 'Red' Barry
— Mike O'Hara, "King Cobra"
Sheila Ryan
— Janet 'J.L.' Brannigan
Tom Brown
— Joe O'Hara
Joseph Crehan
— Oscar Brannigan
John Cason
— Tiger Johnson
Tony Canzoneri
— Swinger Markham
Joey Adams
— Duke Hensel
William Edmunds
— Professor Berger
Edit Angold
— Mama Berger
Margia Dean
— Joy White
Harry Brown
— Fight Manager
Lyle Talbot
— Radio Announcer
Michael Vallon
— Bettor
Sam Flint
— Doctor
Frankie Van
— Referee
Dan Tobey
— Fight Announcer
James J. Casino
— Boxer (uncredited)
Ned Roberts
— Fighter (uncredited)
Jimmy Martin
— Fight Second
Chester Clute
— Timid Man
Jack Perry
— Trainer (uncredited)
John Breen
— Fight Spectoator (uncredited)
Noble 'Kid' Chissell
— Fight Spectator (uncredited)
Bobby Henshaw
— Fight Spectator (uncredited)
Charles Morton
— Fight Spectator (uncredited)
Sol Murgi
— Fight Spectator (uncredited)
Stanley Price
— Fight Spectator (uncredited)
Mark Plant
— Gangster
Harvey Parry
— Bit Role (uncredited)
Al Bain
— Fight Spectator (uncredited)