After coming home, he was elected to the Maine House of Representatives in 1954. He served one term before being elected to the Maine Senate. At the start of his second senate term, he was elected Senate President, an office which in Maine is first in line for the governorship. Upon Clauson's death, Reed became governor and was the fourth Governor Maine had in 1959, after Clauson, Robert Haskell, and Edmund Muskie. He was then elected over Democrat Frank M. Coffin to finish Clauson's term in 1960. He was narrowly reelected over Democrat Maynard C. Dolloff in 1962 to serve Maine's first 4-year term as governor. In 1966, he was defeated by Democrat Ken Curtis.