Robert Stack Eliot Ness Actor Nicholas Georgiade Enrico Rossi Actor Abel Fernandez William Youngfellow Actor Anthony George Guest Star Bruce Gordon Frank Nitti Actor Steve London Actor Walter Winchell Narrator, Producer Frank Wilcox Guest Star Jerry Paris Actor Joe Mantell Guest Star Larry Dobkin Guest Star Nehemiah Persoff Guest Star Phyllis Coates Guest Star Robert Middleton Guest Star Jack Warden Guest Star Lee Van Cleef Guest Star Chuck Hicks Guest Star Mike Kellin Guest Star Percy Helton Guest Star Peter Baldwin Guest Star Quinn Martin Producer Leonard Kantor Writer Aben Kandel Writer Ben Maddow Writer John Peyser Director Robert Florey Director Herbert Abbott Spiro Writer Howard W. Koch Director Walter Grauman Director David Heilweil Producer Stuart Rosenberg Director Joseph Pettracca Writer Josef Shaftel Producer Charles Russell Producer