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