Gen. Leslie Groves
J. Robert Oppenheimer
Leo Szilard
James F. Byrnes
President Harry S. Truman
Gen. George Marshall
Henry Stimson
Dr. Arthur Compton
Franklin D. Roosevelt
Kitty Oppenheimer
Colonel Pash
Edward Teller
Seth
Dwight D. Eisenhower
Groves's Commanding Officer
Ralph A. Bard
Enrico Fermi
Trude Weiss
Colonel Nichols
Eugen Wigner
Albert Einstein
Richard Feynman
Hans Bethe
Samuel Goudsmit
Klaus Fuchs
Lord Rutherford
Haakon Chevalier
Michael Polanyi
Ilse Polanyi
Colonel Lansdale
Robert Wilson
Mrs. Wisnovsky
Jack Wisnovsky
Shapp
Mrs. Trowbridge
Robert Serber
Ed Condon
William 'Deke' Parsons
Captain DeSilva
T. O. Jones
James Tuck
Harry Gold
Army Major
Fleischmann
Haagen Kistiakowski
George Kistiakowski
Kenneth Bainbridge
William D. Leahy
Paul Tibbets
Air Force Guard
Chemist
Alfred MacCormack
Army General
John J. McCloy
Allan Dulles
London Pedestrian
British Jr. Officer
British Sr. Officer
Alexander Sachs
General Pa Watson
Los Alamo Scientist (uncredited)
Scientist (uncredited)
Leo Szilard's Prime Scientist (uncredited)
Writing (Book)
Writing (Teleplay)
Production (Associate Producer)
Production (Producer)
Production (Executive Producer)
Production (Executive Producer)
Sound (Original Music Composer)
Camera (Director of Photography)
Editing (Editor)
Art (Production Design)
Art (Art Direction)
Costume & Make-Up (Makeup Department Head)
Costume & Make-Up (Key Makeup Artist)
Costume & Make-Up (Assistant Hairstylist)
Costume & Make-Up (Hairstylist)
Costume & Make-Up (Assistant Hairstylist)
Production (Executive In Charge Of Production)
Production (Unit Manager)
Production (Unit Production Manager)
Production (Production Manager)
Directing (Third Assistant Director)
Directing (Third Assistant Director)
Directing (Second Assistant Director)
Directing (First Assistant Director)
Directing (Director)
Costume & Make-Up (Costume Design)