 In 1962 Bellotti was elected as Lieutenant Governor for the Commonwealth of Massachusetts from 1963 to 1965.In 1964 he had challenged the sitting governor of his own party, Endicott Peabody, and defeated him in the Democratic Primary; but lost in the general election to John Volpe who thus regained the seat he had lost in 1962.From 1975 to 1987 he served three terms as Massachusetts Attorney General.