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

Mickey Deems

Reinhold Schwimmer

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

Gus Trikonis

Rio

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)

Laura Barry

Girl (uncredited)

Bob Brandon

Capone Board Member (uncredited)

Mushy Callahan

Hood (uncredited)

Mary Grace Canfield

Mrs. Doody, Landlady (uncredited)

Albert Cavens

Reporter (uncredited)

Bud Cokes

Hood (uncredited)

Russ Conway

Interrogator (uncredited)

Yutta D'Arcy

Gangster Girl (uncredited)

Tony Dante

Commuter (uncredited)

Jack Del Rio

Capone Board Member (uncredited)

George DeNormand

Clerk (uncredited)

Paul Frees

Narrator (voice) (uncredited)

Ron Gans

Chapman (uncredited)

James Gonzalez

Party Guest (uncredited)

Michele Guarini

Patsy Lolordo (uncredited)

Phil Harron

Capone Board Member (uncredited)

Jonathan Haze

Gangster Dressed as a Cop (uncredited)

Lisa Jak

Gangster Girl (uncredited)

Betsy Jones-Moreland

Poolside Interviewer (uncredited)

Richard Krisher

Desk Clerk (uncredited)

William Meader

Tenant (uncredited)

Mary Michael

Gangster Girl (uncredited)

Dick Miller

Gangster Dressed as a Cop (uncredited)

Ernesto Molinari

Capone Board Member (uncredited)

Barboura Morris

Jeanette Landsman (uncredited)

Jack Nicholson

Gino, Hit Man (uncredited)

Ron Nyman

Hood (uncredited)

Monty O'Grady

Party Guest (uncredited)

José Portugal

Mourner (uncredited)

Leoda Richards

Party Guest (uncredited)

Jerry Rush

Party Guest (uncredited)

Jeffrey Sayre

Party Guest (uncredited)

Ken Scott

Policeman (uncredited)

Bernard Sell

Hood (uncredited)

Sammy Shack

Vagrant (uncredited)

Joan Shawlee

Edna, Frank's Girlfriend (uncredited)

Buck Taylor

Poolside Interviewer 2 (uncredited)

Corinna Tsopei

Gangster Girl (uncredited)

Patrick Whyte

Judge at Party (uncredited)

Judith Woodbury

Party Guest (uncredited)