Robert Emmet Hannegan was a St. Louis, Missouri politician who served as Commissioner of Internal Revenue from October 1943 to January 1944. He also served as chairman of the Democratic National Committee from 1944 to 1947 and United States Postmaster General from 1945 to 1947. After his political career, in 1947, Hannegan and partner Fred Saigh purchased the St. Louis Cardinals of Major League Baseball. But Hannegan, ill with heart disease, sold his share in the team to Saigh a few months before his death.