From 1921 to 1922, O'Conor served as the assistant
State's Attorney of Baltimore. In 1923, he was elected State's Attorney of Baltimore City, and served there until he was elected as the
Attorney General of Maryland in 1934. O'Conor also served in the National Association of Attorneys General in 1937. His secretary, Camilla Conroy, died in the burning of the luxury liner
SS Morro Castle in 1934. O'Conor identified her body which was found floating face down close to the wreck site. O'Conor was elected as Governor of Maryland in
1938, defeating incumbent
Republican governor
Harry W. Nice. In doing so, he became the first
Roman Catholic of
Irish descent to serve in that position. As governor, O'Conor created the Maryland Council of Defense during the
Second World War. He also worked towards improving the state transportation system, and worked towards the construction of new bridges over the
Susquehanna and
Potomac Rivers. He also worked with other states to encourage inter-state cooperation, and served in positions including the Chairman of the Governor's Conference in 1941, and the President of the Council of State Government in 1943. Near the end of
World War II, O'Conor sought to improve the effects of the War and founded the Commission on Post War Reconstruction and Development. He also sought to improve the Maryland healthcare system. O'Conor was elected to the
United States Senate in
1946, but chose not to run for re-election in
1952. In the Senate, O'Conor served as chairman of the Special Committee on Organized Crime in Interstate Commerce from May to September, 1951, during the Eighty-first Congress. == Death ==