Downs was born on December 2, 1824 in Trumbull County, Ohio. A Congregationalist, Downs married Mary D. Cowen in 1850. They would have four children. Previously, Downs had completed his education at Rush Medical College. During the American Civil War, he served with the 46th Wisconsin Volunteer Infantry Regiment of the Union Army as a surgeon.
Downs was a member of the Assembly in 1855. In 1860, Downs changed his party affiliation from Democratic to Republican. He was a member of the Senate from 1876 to 1877 representing the 28th District. Other positions he held include County Treasurer of Richland County, Wisconsin and Richland County judge.
- Andrew Jackson Aikens & Lewis Amsden Proctor, eds. (1897). Men of Progress. Wisconsin. Evening Wisconsin Company. pp. 155–156.
- Wisconsin Blue Book 2007 - 2008. pp. 104, 135.