A Yale graduate, Washburn parlayed early business success in furniture manufacture into banking and railroads, based in the Connecticut River valley town of Greenfield.

His father was a hat maker from a family with deep colonial roots; Emory Washburn, who was governor of Massachusetts in 1854, was a distant cousin.

Most prominent was the former Congressman and American Civil War general Benjamin F. Butler, who was disliked by the fiscally conservative state Republican establishment over his support for the continued issuance of greenbacks (currency not backed by silver or gold),[14] and who frequently used populist tactics to upset convention proceedings.

Butler's opponents eventually united behind Washburn to give him the nomination, and he won the general election by a 13,000 vote margin over John Quincy Adams II and a labor candidate.

[18] The major event of 1872 during Washburn's tenure as governor was the Great Boston Fire of 1872, which destroyed 65 acres (26 ha) of prime commercial real estate in the city on November 9.

[19] 1873 brought a new round of state funding in the amount of $200,000 to fund the final completion of the Hoosac Tunnel, a tightening of the state's alcohol prohibition laws, and the establishments of a new prison in Concord (now MCI Concord) and a mental hospital in Salem.

[22] He also supported legislation reforming the state's child labor and education laws, which were widely flouted.

After a long and contentious debate involving thirty-three ballots,[25] Washburn was chosen to succeed Sumner as a compromise candidate acceptable to supporters of Henry L. Dawes and George F. Hoar.

[12] Not long after leaving the governorship, Washburn was appointed to a state commission established to investigate the finances and operations of the Hoosac Tunnel,[27] whose construction, originally estimated at $2 million ($70,000,000), had instead cost over $14 million ($390,000,000) and the financing and involvement of the state to complete.

[6] Washburn died in Springfield, Massachusetts, on October 5, 1887, while attending a session of the American Board of Commissioners for Foreign Missions (ABCFM), of which he was a member.