Giuseppe Masseria arrived in New York from Palermo, Sicily in 1902 at the age of 23. Soon he was employed as an enforcer for the gang controlled by Nicholas Morello, an all-Sicilian mob in New York. By 1929 Masseria had laid claim to all the major rackets in the Lower East Side of Manhattan. He built up a team of men who would one day be the major leaders in the world of organized crime.

Joe "the Boss" was the undisputed leader of the New York Sicilian Mafia until the late 1920s when Salvatore Maranzano challenged his position and authority. Maranzano was under the command of Masseria but was determined to build his own empire. The killing that became later known as the Castellammarese War began in February, 1930 when Gaetano Reina, a top aide to Masseria, was shot to death, allegedly the first victim of Maranzano. By April 1931, dozens of men had been killed as the battle raged through the streets of New York. The homicides included the killing of Joseph Catania, a top aide of Masseria, and ultimately concluded with the murder of Masseria himself on April 15, 1931.