Cast
Timothy Webber
Colonel Lansdale
Anne Twomey
Kitty Oppenheimer
Tony Shalhoub
Enrico Fermi
Michael J. Reynolds
Kenneth Bainbridge
Dee McCafferty
William 'Deke' Parsons
Romano Orzari
Leo Szilard's Prime Scientist (uncredited)
Michael Tucker
Leo Szilard
Richard Dysart
President Harry S. Truman
John McMartin
Dr. Arthur Compton
Patrick Breen
Richard Feynman
Hume Cronyn
James F. Byrnes
Lawrence Dane
David Gow
Jack Wisnovsky
George R. Robertson
Ed Condon
David Strathairn
J. Robert Oppenheimer
David Ogden Stiers
Franklin D. Roosevelt
Ron Frazier
Colonel Pash
Barnard Hughes
Henry Stimson
Isabelle Mejias
Mrs. Trowbridge
Scott Thomson
Chemist
Bernie McInerney
Lia Sargent
Mrs. Wisnovsky
Harry Standjofski
Robert Wilson
Ken Pogue
Dwight D. Eisenhower
Gary Reineke
Groves's Commanding Officer
Heinar Piller
Fleischmann
Olek Krupa
Edward Teller
Ron White
Colonel Nichols
Lorne Brass
Klaus Fuchs
Michael Sinelnikoff
Lord Rutherford
Tom Butler
Captain DeSilva
David Ferry
Army Major
Arthur Holden
Scientist (uncredited)
Alan Scarfe
John Seitz
Ralph A. Bard
Vlasta Vrana
Hans Bethe
Roland Hewgill
Army General
Brian Dennehy
Gen. Leslie Groves
Hal Holbrook
Gen. George Marshall
Jonathan Wise
Robert Serber