William S. O'Sullivan
William S. O'Sullivan | |
|---|---|
| Born | January 31, 1928 |
| Died | March 28, 1971 (aged 43) Dorchester, Boston, Massachusetts, U.S. |
| Other names | Billy |
| Occupation | Mobster |
| Spouse | Mary O'Sullivan |
| Children | 6 |
William S. O'Sullivan (January 31, 1928 – March 28, 1971) was an American loanshark and longtime enforcer for Donald Killeen, the head of the Irish mob in South Boston, Massachusetts. O'Sullivan also acted as a mentor to a young James J. Bulger, who grew up to become the leader of Boston's Winter Hill Gang.