Theodore Hall
— Self (archive footage)
Joan Hall
— Self
Joseph Albright
— Self
Marcia Kunstel
— Self
Daniel Axelrod
— Self
J. Michael Wright
— Ted Hall
Lucy Zukaitis
— Joan Hall
Nicolas Eastlund
— Savy Sax
Mickey O'Sullivan
— FBI Agent McQueen
Tom Goodwin
— FBI Agent 3
Zach Twardowski
— Ed Hall
Olivia Piper
— Young Ruthie
Enzo Inalsingh
— Sax baby
Kate Marie Smith
— Susan Sax
Leslie Groves
— Self (archive footage) (uncredited)
J. Robert Oppenheimer
— Self (archive footage) (uncredited)
Joseph E. Davies
— Self (archive footage) (uncredited)
Walter Huston
— Self (archive footage) (uncredited)
Ann Harding
— Self (archive footage) (uncredited)
Manart Kippen
— Self (archive footage) (uncredited)
Harry S. Truman
— Self (archive footage) (uncredited)
Dwight D. Eisenhower
— Self (archive footage) (uncredited)
Henry L. Stimson
— Self (archive footage) (uncredited)
Joseph Staline
— Self (archive footage) (uncredited)
Paul Tibbets
— Self (archive footage) (uncredited)
Julius Rosenberg
— Self (archive footage) (uncredited)
Ethel Rosenberg
— Self (archive footage) (uncredited)