Mike Rounds is an American businessman and politician serving as the junior United States senator from South Dakota since 2015. A member of the Republican Party, he served as the 31st governor of South Dakota from 2003 to 2011, and in the South Dakota Senate from 1991 to 2001. In 2014, Rounds was elected to the United States Senate, succeeding retiring Democrat Tim Johnson. He was reelected in 2020 over Democratic nominee Dan Ahlers.