Robert Stack
— Eliot Ness (archive footage)
Neville Brand
— Al Capone (archive footage)
Paul Bruce
Richard Carlyle
Lewis Charles
Russ Conway
Abel Fernandez
— William Youngfellow (archive footage)
Eddie Firestone
Nicholas Georgiade
— Enrico Rossi (archive footage)
Bruce Gordon
— Frank Nitti (archive footage)
John Hoyt
— Capone's attorney (archive footage)
Charles Lane
Frank London
Steve London
— Jack Rossman (archive footage)
Gavin MacLeod
Gregg Palmer
Paul Picerni
— Agent Lee Hobson (archive footage)
Lalo Rios
William Schallert
Robert F. Simon
James Westerfield
Frank Wilcox
— U.S. Attorney Beecher Asbury (archive footage)