After settling in the Lower East Side of New York, he joined the Mafia family led by capo di tutti capi Salvatore D'Aquila.
During this period, Umberto Valenti had run afoul of his boss, Salvatore D'Aquila, and was one of twelve men (including Giuseppe Morello, Ignazio Lupo, Ciro Terranova and others) marked for death.
Upon his return to America in January 1922, Valenti attempted to make amends with D'Aquila by eliminating his chief rival, Vincenzo Terranova.
Mere hours later, Terranova's underboss Silva Tagliagamba was fatally wounded in Lower Manhattan by Valenti and gunmen working for him.
[5] Forty-eight hours later, on August 11, Umberto Valenti attended a sit-down meeting with Masseria and others in a cafe at the corner of Second Avenue and E. 12th Street.
Apparently, realizing his life was in danger, Valenti burst from the table and ran outside as the bullets began flying.
Valenti, gravely injured by gunfire, managed to make it on the running board of a passing taxi before collapsing onto the pavement where he died.