Warren Beatty as John Reed

Diane Keaton as Louise Bryant

Edward Herrmann as Max Eastman

Jerzy Kosiński as Grigory Zinoviev

Jack Nicholson as Eugene O'Neill

Paul Sorvino as Louis Fraina

Maureen Stapleton as Emma Goldman

Nicolas Coster as Paul Trullinger

M. Emmet Walsh as Speaker at Liberal Club

Ian Wolfe as Mr. Partlow

Bessie Love as Mrs. Partlow

MacIntyre Dixon as Carl Walters

Pat Starr as Helen Walters

Eleanor D. Wilson as Mrs. Reed

Max Wright as Floyd Dell

George Plimpton as Horace Whigham

Harry Ditson as Maurice Becker

Leigh Curran as Ida Rauh

Kathryn Grody as Crystal Eastman

Brenda Currin as Marjorie Jones

Nancy Duiguid as Jane Heap

Norman Chancer as Barney

Dolph Sweet as Big Bill Haywood

Ramon Bieri as Police Chief

Jack O'Leary as Pinkerton Guard

Gene Hackman as Pete van Wherry

Gerald Hiken as Dr. Lorber

William Daniels as Julius Gerber

Dave King as Allan Benson

Joseph Buloff as Joe Volski

Stefan Gryff as Alex Gomberg

Denis Pekarev as Interpreter in Factory

Roger Sloman as Vladimir I. Lenin

Stuart Richman as Leon Trotsky

Oleg Kerensky as Alexander Kerensky / Himself - Witness

Nikko Seppala as Young Bolshevik Soldier

John J. Hooker as Senator Overman

Shane Rimmer as MacAlpine

Jerry Hardin as Harry

Jack Kehoe as Eddie

Christopher Malcolm as CLP Party Member #1

Tony Sibbald as CLP Party Member #2

R.G. Armstrong as Government Agent

Josef Sommer as State Department Official

Jan Tříska as Karl Radek

Åke Lindman as Scandinavian Escort

Pertti Weckström as Finnish Doctor

Nina Macarova as Russian Nurse

Jose De Fillippo as Russian Doctor

Andreas La Casa as Little Boy

Roger Baldwin as Himself - Witness

Henry Miller as Himself - Witness

Adela Rogers St. Johns as Herself - Witness

Dora Russell as Herself - Witness

Scott Nearing as Himself - Witness

Tess Davis as Herself - Witness

Heaton Vorse as Herself - Witness

Hamilton Fish as Himself - Witness

Isaac Don Levine as Himself - Witness

Rebecca West as Herself - Witness

Will Durant as Himself - Witness

Will Weinstone as Himself - Witness

Emmanuel Herbert as Himself - Witness

Arne Swabeck as Himself - Witness

Adele Gutman Nathan as Herself - Witness

George Seldes as Himself - Witness

Kenneth Chamberlain as Himself - Witness

Blanche Hays Fagen as Herself - Witness

Galina von Meck as Herself - Witness

Art Shields as Himself - Witness

Andrew Dasburg as Himself - Witness

Hugo Gellert as Himself - Witness

Dorothy Frooks as Herself - Witness

George Jessel as Himself - Witness

Jacob Bailin as Himself - Witness

John Ballato as Himself - Witness

Lucita Williams as Herself - Witness

Bernadine Szold-Fritz as Herself - Witness

Jessica Smith as Herself - Witness

Harry Carlisle as Himself - Witness

Arthur Mayer as Himself - Witness

Miriam Margolyes as Woman with Notebook (uncredited)

John Ratzenberger as Communist Leader (uncredited)

Simon Jones as Louise Bryant's Colleague in France (uncredited)

Jill Goldston as Dancing Woman (uncredited)