Eliot Ness
Frank Nitti
Giuseppe 'Joe' Zangara
Jake 'Dodo' Ryan
Mayor Anton J. Cermak
Enrico Rossi
William Youngfellow
Jack Rossman
Cam Allison Jr.
Louis Campagne
Frank Diamond
Bill Skidmore
News Vendor
Ira Peterson (as George Neise)
Milwaukee Minelli (as John Duke)
Sally Jansen
Tom A. Jansen (as John Day)
Mrs. Swoboda
Roley Sutton
Narrator (voice)
Self (archive footage)
Reporter (uncredited)
Albert (uncredited)
Counterman (uncredited)
Hood (uncredited)
Observer at Scene (uncredited)