Robert E. Hannegan was born June 30, 1903 in St. Louis, Missouri. He received his LL.B. degree in 1925 from St. Louis University. From 1925 to 1942 he practiced law in St. Louis. From 1933 1942 he served as Chairman of the Democratic City Committee of St. Louis and during this time became the chief aid to Mayor Bernard F. Dickmann, and the boss of the twenty-first ward in St. Louis. From 1942 to 1943 he was Collector of Internal Revenue for the Eastern District of Missouri, and from 1943 to 1945 he was the Commissioner of Internal Revenue. From 1944 to 1947 he served as Chairman of the Democratic National Committee. From 1945 to 1947 he was Postmaster General of the United States, and from 1947 to 1949 served as President of the Cardinal National League Baseball Organization. Hannegan died in St. Louis on October 6, 1949.
From the description of Hannegan, Robert E. (Robert Emmet), 1903-1949 (U.S. National Archives and Records Administration). naId: 10573202