All the Events of The Irishman in Chronological Order, Because It's Just a Little Confusing

Once Sheeran had earned Bufalino's trust, the mob boss decided to introduce Sheeran to Jimmy Hoffa in 1957. Hoffa was an infamous labor union leader who then served as the president of the International Brotherhood of Teamsters, a union that historically suffered from corruption and control by organized crime, including the Mafia.

The union leader was in need of a hitman, and Bufalino thought Sheeran was the right man for the job. Hoffa agreed, and Sheeran became a close confidante of Hoffa, eventually earning the position of a top Teamsters Union official. Even while he grew closer to Hoffa, Sheeran continued to act as the Bufalino crime family hitman and top aide to Bufalino himself.