- "You're a diplomat young man, we have a deal."
- ―Moose Mangano to Aldo Trapani[src]
Mangano moved to New York in order to gain a foothold for his uncle, Samuele Mangano. He fell in with the Tattaglias and managed to become racket boss of Poppy's in Hell's Kitchen, earning a tough reputation, so much so that citizens of Hell's Kitchen would remark 'Don't mess with the Moose'.
After he was bought out by Aldo Trapani, Mangano informed his Godfather of Trapani's prowess and the Don began to make deals with the Corleone family when he arrived from United States and entered Sicily in 1956.