Mark Dayton (born January 26, 1947) is a Democratic US Senator from Minnesota who took office in 2001. He was born in Minneapolis, Minnesota. Dayton graduated cum laude Yale University, 1969. He was an unsuccessful candidate for the United States Senate in 1982. Dayton had served as a legislative assistant to Senator Walter Mondale. He was Minnesota state auditor, 1991–1995 and elected to the United States Senate in 2000. He defeated incumbent Rod Grams.