Sam Waterston

Robert Oppenheimer

John Carson

Narrator

Shane Rimmer

Ed Condon

Alexander Knox

Henry Stimson

Jana Shelden

Kitty Oppenheimer

Phil Brown

Lewis Strauss

Edward Hardwicke

Enrico Fermi

David Suchet

Edward Teller

James Maxwell

Lloyd Garrison

Milton Johns

George Kistiakowsky

Barry Dennen

Isidor Rabi

Bob Sherman

Ernest Lawrence

Matthew Guinness

Hans Bethe

Christopher Malcolm

Steve Nelson

Garrick Hagon

Frank Oppenheimer

David Baxt

Colonel John Lansdale

Peter Banks

Joseph Volpe

Ron Berglas

John Manley

Colin Bennett

Seth Neddermeyer

Christopher Muncke

Colonel Kenneth Nichols