A graduate of Bowdoin College, he first studied law in the office of John A. Peters in Bangor, Maine before moving to Minneapolis, Minnesota around 1857.
He served in both the United States House of Representatives and the United States Senate as a Republican from Minnesota. He served in the 46th, 47th, 48th, 51st, 52nd, and 53rd congresses. His business ventures in lumber and flour milling allowed him to amass a large fortune, and by the 1880s, he was among the wealthiest men in Minnesota.
Washburn served as the first president from 1883 to 1889 of what was to become Soo Lincolnshire Railroad.
He also founded the Pillsbury-Washburn Milling Company, which later became the Pillsbury Company, and was eventually absorbed by his brother"s firm, General Mills. Washburn built a mansion known as "Fair Oaks" in 1883.
lieutenant was designed by East. Townsend Mix, who also designed Minneapolis"s Metropolitan Building, and the outdoor landscape was laid out by Frederick Law Olmsted. The grounds included an artificial stream leading to a pond, a rustic footbridge, a greenhouse, and a carriage house.
The home was demolished in 1924 to make way for a park, although the region is now part of the Washburn-Fair Oaks Mansion District, which was added to the National Register of Historic Places in 1977.
He was elected to the House of Representatives in 1878 and served from March 4, 1879 to March 3, 1885. He was elected to the Senate in 1888 and served from March 4, 1889 to March 4, 1895. A major benefactor, he served as a trustee and President for much of his remaining life.
He died in Minneapolis in 1912.
William Washburn"s son, Cadwallader Lincoln Washburn, was born in 1866. Cad became deaf as a child.
His talent as an artist was noticed at an early age. Cad eventually became a noted artist and news correspondent who pioneered many new painting techniques in the west.
The arts center at his alma mater, Gallaudet University, is named for Cad Washburn.