| Actor | James Gregory (as Sgt. Schaefler), Martin Balsam (as Mac Keeley), Nehemiah Persoff (as Johnny Torrio), Murvyn Vye (as George 'Bugs' Moran), Robert Gist (as Dion O'Banion), Lewis Charles (as Earl Weiss), Joe De Santis (as Big Jim Colosimo), Sandy Kenyon (as Bones Corelli), Raymond Bailey (as Lawyer Brancato), Al Ruscio (as Tony Genaro), Louis Quinn (as Joe Lorenzo), Ron Soble (as John Scalisi), Steve Gravers (as Albert Anselmi), Raikin Ben-Ari (as Ben Hoffman) |
| Actress | Fay Spain (as Maureen Flannery) |
| Assistant | Lindsley Parsons Jr. (as Assistant Director), Phil Rawlins (as Assistant Director ( Uncredited )) |
| Creator | Russell Hanlin (as Costume Design), Sabine Manela (as Costume Design), Forrest T. Butler (as Costume Design ( Uncredited )), Dave Grayson (as Make-up), Dave Koehler (as Special Effects) |
| Director | Richard Wilson* |
| Director Of Photography | Lucien Ballard |
| Film Editor | Walter Hannemann |
| Music | David Raksin |
| Narrator | James Gregory |
| Producer | Leonard Ackerman, John H. Burrows |
| Production Company | Allied Artists Pictures |
| Production Designer | Hilyard M. Brown |
| Sound | Tom Lambert, Joseph Keener (as Uncredited) |
| Starring | Rod Steiger (as Al Capone) |
| Writer | Malvin Wald, Henry F. Greenberg |
