On May 26, 1938, Father Thomas J. McDonough was ordained a priest. Pope Pius XII appointed him Titular Bishop of Thaenae and Auxiliary Bishop of St. Augustine on March 10, 1947. He was consecrated on April 30, 1947, the youngest American bishop at that time.

Ten years later, on January 2, 1957, Bishop McDonough was transferred to Savannah as Auxiliary to Archbishop Gerald P. O’Hara, Bishop of Savannah and Apostolic Delegate to England and Wales. Bishop McDonough was installed on February 20, 1957. When Archbishop O’Hara resigned in 1959, Bishop McDonough served as diocesan administrator until he was appointed 10th Bishop of Savannah on March 2, 1960. He was installed April 27, 1960. His great priority was cultivating seminarians and priests, so he established Saint John Vianney Minor Seminary and arranged for about 30 Irish priests to come to the diocese.

Bishop McDonough attended all four sessions of the Second Vatican Council (1962-65) and helped weather the storms of the civil rights movement. On March 1, 1967, Pope Paul VI promoted Bishop McDonough to head the Archdiocese of Louisville, where he remained until his resignation on September 29, 1981. Archbishop McDonough died on August 4, 1998.