Campbell Scott as Self - Narrator (voice)

Boyd Gaines as Chairman Gray (voice)

Daniel Gerroll as Colonel Pash

Michael Stuhlbarg as Edward Teller

Ellen Katz as The Stenographer

Michael Cumpsty as

Harold Agnew as Self

Jeremy Bernstein as Self

Freeman Dyson as Self

Richard Rhodes as Self

Martin J. Sherwin as Self

Joseph McCarthy as Self (archive footage)

J. Robert Oppenheimer as Self (archive footage)

David Strathairn as J. Robert Oppenheimer

Herbert York as Self

Marvin L. Goldberger as Self

Priscilla McMillan as Self

Robert Christy as Self

Roy Glauber as Self

Harry S. Truman as Self (Archive Footage)

J. Edgar Hoover as Self (archive footage)

Lewis Strauss as Self (archive footage)

Dwight D. Eisenhower as Self (archive footage)

Eleanor Roosevelt as Self (archive footage)

Edward Teller as Self (archive footage)

Lyndon B. Johnson as Self (archive footage)