| Episode credited cast: |
 | Will Rosser | - | Narrator (voice) |
| Anthony Summers | - | Himself - Author of 'The Secret Life of J. Edgar Hoover' |
| John Fox | - | Himself - FBI Historian |
| William Gallinaro | - | Himself - Crime Detective |
| Athan Theoharis | - | Himself - Author of 'The FBI and American Democracy' |
| Curt Gentry | - | Himself - Author of 'J. Edgar Hoover: The Man and the Secrets' |
| John M. Dowd | - | Himself - US Justice Department (as John Dowd) |
| William Turner | - | Himself - Former FBI Agent (as Bill Turner) |
| Bill Bonanno | - | Himself - Son of Mafia Boss Joseph Bonanno |
| Rest of cast listed alphabetically: |
| Inga Arvad | - | Herself, Danish journalist (archive footage) |
 | Milton Berle | - | Himself (archive footage) |
| Joseph Bonanno | - | Himself, mobster (archive footage) |
 | Judy Cerda | - | Louisa Stewart |
| Frank Costello | - | Himself, mobster (archive footage) |
| John Dillinger | - | Himself (archive footage) |
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