Jason Robards

Al Capone

George Segal

Peter Gusenberg

Ralph Meeker

George Clarence 'Bugs' Moran

Jean Hale

Myrtle

Clint Ritchie

Jack McGurn

Frank Silvera

Nick Sorello

Joseph Campanella

Albert Wienshank

Richard Bakalyan

John Scalise

David Canary

Frank Gusenberg

Bruce Dern

Johnny May

Harold J. Stone

Frank Nitti

Kurt Kreuger

James Clark

Paul Richards

Charles Fischetti

Joe Turkel

Jake 'Greasy Thumb' Guzik

Milton Frome

Adam Heyer

John Agar

Dion O'Bannion

Celia Lovsky

Josephine Schwimmer

Tom Reese

Ted Newberry

Jan Merlin

Willie Marks

Alexander D'Arcy

Joe Aiello

Reed Hadley

Hymie Weiss

Charles Dierkop

Salvanti

Tom Signorelli

Bobo Borotto

Rico Cattani

Albert Anselmi

Alex Rocco

Diamond

Leo Gordon

Heitler

Daniel Ades

Angelo Molina (uncredited)

Vincent Barbi

Witness (uncredited)

Mary Grace Canfield

Mrs. Doody, Landlady (uncredited)

Russ Conway

Interrogator (uncredited)

Paul Frees

Narrator (voice) (uncredited)

Jonathan Haze

Gangster Dressed as a Cop (uncredited)

Betsy Jones-Moreland

Poolside Interviewer (uncredited)

Mary Michael

Gangster Girl (uncredited)

Dick Miller

Gangster Dressed as a Cop (uncredited)

Barboura Morris

Jeanette Landsman (uncredited)

Jack Nicholson

Gino, Hit Man (uncredited)

Ron Nyman

Hood (uncredited)

Monty O'Grady

Party Guest (uncredited)

Leoda Richards

Party Guest (uncredited)

Jeffrey Sayre

Party Guest (uncredited)

Ken Scott

Policeman (uncredited)

Joan Shawlee

Edna, Frank's Girlfriend (uncredited)

Buck Taylor

Poolside Interviewer 2 (uncredited)

Corinna Tsopei

Gangster Girl (uncredited)