Muhammad Ali as Cassius Clay / Muhammad Ali

Ernest Borgnine as Angelo Dundee

John Marley as Dr. Ferdie Pacheco

Lloyd Haynes as Herbert Muhammad

Lucille Benson as Mrs. Fairlie

Sally Bondi as Bess

Malachi Throne as Payton Jory

Teddy Wilson as Joe The Gardener

Annazette Chase as Belinda Ali

Mira Waters as Ruby Sanderson

Chip McAllister as Cassius Clay aged 18

Drew Bundini Brown as Himself

Robert Duvall as Bill McDonald

David Huddleston as Cruikshank

Ben Johnson as Hollis

James Earl Jones as Malcolm X

Dina Merrill as Velvet Green

Roger E. Mosley as Sonny Liston

Paul Winfield as Draft Lawyer

Richard Gullage as Commission Doctor

Arthur Adams as Cassius Clay Sr.

Dorothy Meyer as Odessa Clay

Rahman Ali as Rahman Ali

Howard Bingham as Howard Bingham

Richard Venture as Colonel

Stack Pierce as Rahaman

W. Youngblood Muhammad as W. Youngblood Muhammad

Ven Medina as Ronnie

Paul Mantee as Carrara

Skip Homeier as Major

Lloyd Wells as Lloyd Wells

George Garro as Mr.Curtis

David Clennon as Captain

Ernie Wheelwright as Bossman Jones

Pat Patterson as Pat Patterson

George Cooper as Lawyer

James Gammon as Mr. Harry

Gene Kilroy as Gene Kilroy

Toni Crabtree as Hooker

Sally Gries as Sponsor's Wife

Elizabeth Marshall as Sponsor's Wife

Don Dunphy as Commentator

Fernand A. Larrieu Jr. as Grocer

Nai Bonet as Suzie Gomez

Harold Conrad as Harold Conrad

Alberto Martín as Doctor

Walter Olkewicz as Reporter

Roy Firestone as TV Reporter (uncredited)