Born in Rockford, Illinois, Anderson practiced law after serving in the Army during World War II. After a stint in the United States Foreign Service, he won election as the State's Attorney for Winnebago County, Illinois. He won election to the House of Representatives in 1960 in a strongly Republican district. Initially one of the most conservative members of the House, Anderson's views moderated during the 1960s, particularly regarding social issues. He became Chairman of the House Republican Conference in 1969 and remained in that position until 1979. He strongly criticized the Vietnam War as well as President Richard Nixon's actions during the Watergate scandal.