He was a member of the Minnesota State Senate from January, 1903 to January, 1907. He was elected Lieutenant Governor in 1906. He became the 17th Governor of Minnesota on September 21, 1909, when Governor John Albert Johnson died, and served until January 5, 1915. Eberhart was a Republican. Minnesota elected Governors and Lt. Governors on separate ballots until 1974, so it happen occasionally that the two were of different parties.