 He served as a state Assistant District Attorney from 1929 to 1938 before becoming a clerk to two Supreme Court Justices, first Peter Schmuck, and later Joseph A. Gavagan.He was reportedly a close associate of gangster Tommy Lucchese, who helped Impellitteri's rise in politics.On the other hand, a report in the "New York World-Telegram" indicated that Impelliteri opposed organized crime and corruption, and had failed to rise through the city Democratic Party's ranks because he had "the injudicious good taste to snub Frank Costello", the gambler and racketeer who was said to control the Tammany Hall organization behind the scenes.