Jackson was raised in Everett and earned the nickname Scoop in the 1920s when he delivered 74,880 copies of The Everett Herald without a complaint. He became a Snohomish County prosecutor and was elected to the U.S. House of Representatives in 1940 as a Democrat from the 2nd Congressional District.
In 1952, he was elected to the Senate where he became an advocate of a strong defense. In 1960, he was under serious consideration as the running mate of Democratic presidential candidate John F. Kennedy (1917-1963). Jackson ran for president twice. In 1968, he was offered the post of Secretary of Defense by Republican President-elect Richard M. Nixon (1913-1994), but Jackson declined.
During the Vietnam War, Jackson was a "hawk" (Seattle P-I). Supporters of U.S. policies in Vietnam were known as "hawks." People opposed to the war were known as "doves."
After Jackson's death, Governor John Spellman (b. 1926) appointed former Governor Daniel J. Evans to Jackson's seat in the Senate (on September 8, 1983). Evans resigned as head of The Evergreen State College and as head of the Northwest Power Planning Council.
Jackson was stricken at his home in Everett and was pronounced dead at a hospital. He is buried at Evergreen Cemetery in Everett.