| Johnny Columbo | 吉恩·凯利
 | |
| Erico Naples Bus Boy (uncredited) | 罗伯特·布莱克
 | |
| Louis Lorelli | 卡罗尔·耐什
 | |
| Isabella Gomboli | Teresa Celli | |
| Caesar Xavier Serpi | Marc Lawrence | |
| Carlo Sabballera | Frank Puglia | |
| Capt. Thompson | Barry Kelley | |
| Benny Danetta | Mario Siletti | |
| George Allani | Carl Milletaire | |
| Roberto Columbo | Peter Brocco | |
| Maria Columbo (as Eleonora Mendelssohn) | Eleonora von Mendelssohn | |
| Mrs. Danetta | Grazia Narciso | |
| Moriani | Maurice Samuels | |
| Judge | Burk Symon | |
| Prosecutor | Bert Freed | |
| Mrs. Sabballera | Mimi Aguglia
 | |
| Bettini | Baldo Minuti | |
| Pietro Riago | Carlo Tricoli | |
| Lombardi | Marc Krah | |
| Rudi Gomboli | Jimmy Lagano | |
| Mary the Shamrock | Phyllis Morris | |
| Mr. Larti (uncredited) | John Ardizoni | |
| Footpad (uncredited) | John Bagni | |
| Defense Attorney (uncredited) | Tony Barrett
 | |
| Policeman (uncredited) | Ray Bennett | |
| Translator (uncredited) | Dino Bolognese | |
| Saturnine (uncredited) | Alfred Allegro | |
| Laborer (uncredited) | Eugene Borden | |
| Tourist (uncredited) | Lillian Bronson | |
| Don Giuseppe (uncredited) | John Carboni | |
| Translator (uncredited) | Peter Cusanelli | |
