Stevens was born in Indianapolis, Indiana in 1923. He fought as a pilot in the Pacific during World War II. Later, he would graduate from UCLA and Harvard Law School. In the early 1950s he moved to Alaska where he practiced law. In 1953 he was appointed U.S. Attorney in Fairbanks, before transferring to Washington, DC in 1956.
In 1960, President Eisenhower appointed him Solicitor of the Department of the Interior. After returning to Alaska, he was elected to the Alaska House of Representatives in 1964. He was appointed by Governor Walter Joseph Hickel to the United States Senate in 1968 following the death of E.L. (Bob) Bartlett. He was re-elected in a special election in 1970. In 1972 he was elected to his first full term and has served in the Senate ever since. He became President pro tempore of the Senate when Republicans regained control of the chamber in 2003. He is also Chairman of the powerful Appropriations Committee.