After Representative Archibald Hill Carmichael announced his retirement in 1936, Sparkman ran in the Democratic primary for the open seat. A teacher of the Big Brother Class at the First Methodist Church in Huntsville, his campaign was successfully launched through fundraising, campaigning and advertising by students in his Sunday class. Sparkman was elected to the United States House of Representatives in the United States House elections, 1936, defeating Union Party (United States) candidate, architect Harry J. Frahn with 99.7% of the vote. He was reelected in United States House elections, 1938, United States House elections, 1940, United States House elections, 1942, and United States House elections, 1944, serving in the 75th United States Congress, 76th United States Congress, 77th United States Congress, 78th United States Congress, and 79th United States Congress. In 1946 he served as Party whips of the United States House of Representatives. He was reelected in the United States House elections, 1946 to the 80th United States Congress and on the same date was United States Senate elections, 1946 in a special election to fill the vacancy caused by the death of John H. Bankhead II, for the term ending on January 3, 1949. Sparkman resigned from the House of Representatives immediately following the election and began his Senate term on November 6, 1946. He served until his retirement on January 3, 1979, having not sought reelection in United States Senate elections, 1978.

Did Sparkman serve longer in the House or the Senate?
Senate