Joseph Michael Valachi (September 22, 1904 – April 3, 1971) was an American gangster in the Genovese crime family who is notable as the first member of the Italian-American Mafia to acknowledge its existence publicly.
He is credited with popularization of the term cosa nostra.In 1963, Valachi testified before a U.S.
Senate committee, known as the Valachi hearings, and disclosed previously unknown information about the Italian-American Mafia including its structure, operations, rituals and membership.
His testimony was the first major violation of omertà , the mafia's code of silence, and the first concrete evidence that the Italian-American Mafia existed to federal authorities and the general public.
Valachi died in 1971 while he was serving a life sentence at the Federal Correctional Institution, La Tuna.