Marion Michael Rounds (born October 24, 1954) 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. Rounds was raised in Pierre, South Dakota. He attended South Dakota State University, where he earned his Bachelor of Science degree. He was elected to the South Dakota Senate in 1990, representing the 24th district until 2001. Rounds ran for governor of South Dakota in 2002, and after an upset victory in the Republican primary, won the general election. He was reelected in 2006. In 2014, Rounds was elected to the United States Senate, succeeding retiring Democrat Tim Johnson. He was reelected in 2020.