William O’Dwyer (11 July 1890 – 24 November 1964) was the 100th Mayor of New York City from 1946 to 1950.
O’Dwyer was born in County Mayo and migrated to the United States in 1910, after abandoning studies for the priesthood. He worked as a laborer, then as a New York City police officer, while studying law at night at Fordham University Law School. He received his degree in 1923 and then built up a successful law practice before serving as a Kings County, New York Court judge. He won election as the Kings County District Attorney in 1939 and his prosecution of the organized crime syndicate known as Murder, Inc. made him a national celebrity.
After losing the mayoral election to Fiorello LaGuardia in 1941, O’Dwyer enlisted in the Army, achieving the rank of Brigadier General.
William O’Dwyer died in New York City on 24 November 1964, at the age of 74, and was buried in Arlington National Cemetery.