 He served as secretary on the Moorestown Township, New Jersey Board of Adjustment from 1948 to 1952, was a member of the Moorestown Committee from 1953 to 1962, serving as Mayor of Moorestown, New Jersey from 1957 to 1962, and was chairman of the Moorestown Planning Board from 1962 to 1963.He was a member of the executive board of the New Jersey State League of Municipalities from 1958 to 1962.Forsythe was elected to the New Jersey Senate, where he served from 1964 to 1970.