Rod Steiger
Al Capone
Martin Balsam
Mac Keeley, reporter
Nehemiah Persoff
Johnny Torrio
Raymond Bailey
Lawyer Brancato
Robert Gist
Dion O'Banion
James Gregory
Schaefler (narrator)
Murvyn Vye
George 'Bugs' Moran
Paul Bryar
Police Inspector (uncredited)
Mauritz Hugo
Hood (uncredited)
Al Ruscio
Tony Genaro
Dan Riss
Voice of Radio Announcer (uncredited)
Lewis Charles
Earl Weiss
Joe De Santis
Big Jim Colosimo
Fay Spain
Maureen Flannery
Forbes Murray
Pallbearer at Colosimo's Funeral (uncredited)
Louis Quinn
Joe Lorenzo
Allen Jaffe
Bodyguard
Sandy Kenyon
Bones Corelli
Ron Soble
John Scalisi
Ralph Brooks
Convict in Yard at Alcatraz
Fred Sherman
Storekeeper (uncredited)
Clegg Hoyt
Lefty
Larry Chance
Vincent (uncredited)
Charles Sherlock
Reporter (uncredited)
Fred Aldrich
Funeral Spectator
James Bacon
Reporter
Paul Bradley
Benefit Guest