He was a dedicated conservationist who delivered the keynote address at MIT on the first Earth Day in 1970. He had ealier served as state commissioner of natural resources for 10 years.
He was elected Lieutenant Governor in 1966, and in 1969, he succeeded Republican John Volpe as governor when Volpe became secretary of Transportation under President Nixon. In 1970, Gov. Sargent won re-election.
He was governor of the Commonwealth during the strife following Judge Arthur Garrity's 1974 decision to desegregate Boston public schools by means of forced busing. He was accused of practicing NIMBY (not-in-my-backyard) politics by supporting the decision while remaining unaffected in the very wealthy suburban town of Dover, Massachusetts. On occasion, busloads of anti-busing protesters from the city, found out that his road in Dover had no street lights when they showed up at night to picket.