Garland was a officer and director of Garland Manufacturing Company in Saco and Snocraft Company in Norway. He served as an enlisted man in the United States Air Corps from 1943 to 1946.
Director of the New England Council and Associated Industries of Maine from 1955 to 1957, he was a member of the Saco Superintending School Committee, 1952-1954 and mayor of Saco, 1956-1959. He then served as New England field adviser to the Small Business Administration, 1958-1960.
Elected as a Republican to the Eighty-seventh Congress (January 3, 1961-January 3, 1963), he was an unsuccessful candidate for renomination in 1962 and again as a candidate for Congress in 1966.
Garland then became the town manager in Gorham from 1967 to 1969. After becoming the marketing director for an engineering firm (1970-1972), he returned to municipal management acting as city manager in Claremont, New Hampshire (1972-1973) and community manager of Ocean Pines in Ocean City, Maryland (1973-1974). He returned to Maine serving as the town manager of Searsport (1974-1981), then as city manager in Bath from 1981 though 1989.
Peter Garland died on January 26, 2005.