In 1943, Mike Mansfield served Montana as Representative and Senator in the U.S. Congress for thiry-four years, and his actions had an enduring impact in the Big Sky state. Mansfield served as a Representative from 1943-1952, and U.S. Senator from 1952-1977 serving as chairman, Special Committee on Campaign Expenditures, Democratic whip (1957-1961), majority leader (1961-1977), chairman, Committee on Rules and Administration, Select Committee on Secret and Confidential Documents, and Special Committee on Secret and Confidential Documents.

Manfield also server as Ambassador to Japan from 1977-1988; and was awarded the Presidential Medal of Freedom in 1989.