Can't disagree with Gambino and Accardo. But my vote goes to Charlie Luciano, the founding father of the modern American Mafia. He got rid of the Moustache Petes (Masseria and Maranzano), founded the Commission, and accepted partnership from non-Sicilians and even non-Italians, if they had something to contribute.

Ntra la porta tua lu sangu � sparsu,
E nun me mporta si ce muoru accisu...
E s'iddu muoru e vaju mparadisu
Si nun ce truovo a ttia, mancu ce trasu.