- J. Robert Oppenheimer
- Self
- Kai Bird
- Self - Co-author, American Prometheus
- Ellen Bradbury
- Self - Daughter of Los Alamos scientist
- Alan B. Carr
- Self - Senior historian, Los Alamos National Laboratory
- Jennet Conant
- Self - Author, 109 East Palace
- Albert Einstein
- Self
- David Eisenbach
- Self - History professor, Columbia University
- Jon Else
- Self - Filmmaker, The Day After Trinity
- Leslie Groves
- Self
- Gregg Herken
- Self - Author, Brotherhood of the Bomb
- Adolf Hitler
- Self
- Michio Kaku
- Self - Theoretical physicist
- Joseph McCarthy
- Self
- Christopher Nolan
- Self - writer / director: 'Oppenheimer'
- Bill Nye
- Self - Science educator
- Charles Oppenheimer
- Self - Grandson
- Richard Rhodes
- Self - Author, The Making of the Atomic Bomb
- Eleanor Roosevelt
- Self
- Franklin D. Roosevelt
- Self
- Mareena Robinson Snowden
- Self - Nuclear security expert
- Joseph Stalin
- Self
- Lewis Strauss
- Self
- Edward Teller
- Self
- Harry S. Truman
- Self
- Alex Wellerstein
- Self - Nuclear historian
- Judy Woodruff
- Self
