William Aloysius O'Connor

William Aloysius O'Connor (December 27, 1903 – November 14, 1983) was an American prelate of the Roman Catholic Church. He served as Bishop of Springfield in Illinois from 1949 to 1975.

William O'Connor was born in Chicago, Illinois, to John and Mary (née Murphy) O'Connor. His brother was longtime Chicago newsman Len O'Connor. He attended Archbishop Quigley Preparatory Seminary from 1917 to 1922, and St. Mary of the Lake Seminary in Mundelein from 1922 to 1928. He was ordained to the priesthood by Cardinal George Mundelein on September 24, 1927. He then furthered his studies in Rome at the Propaganda College, from where he obtained a doctorate in sacred theology in 1930.

Upon his return to the United States in 1930, O'Connor served as a professor at Archbishop Quigley Preparatory Seminary until 1935. He briefly attended New York School of Social Work (1935-1936) before becoming superintendent of St. Mary's Training School at Des Plaines in 1936. He was named supervisor of Catholic Charities in the Archdiocese of Chicago in 1938, and president of the National Conference of Catholic Charities in 1944. He was raised to the rank of a Domestic Prelate in March 1946. He also served on the advisory board of the War Relief Services in the National Catholic Welfare Council and as director of the USO Council of Chicago.