Herter next worked for Herbert Hoover in the American Relief Association. When Hoover became secretary of commerce in 1921, Herter spent three years as his assistant before returning to Boston. In 1931 Herter began twelve years—four as Speaker—in the Massachusetts House of Representatives, followed by five terms (1943–1953) as U.S. congressman for Massachusetts and two terms (1953–1957) as governor of Massachusetts. An internationalist Republican, Herter strongly supported the creation of the United Nations (UN) and the Marshall Plan.
Named undersecretary of state in 1957 on the recommendation of Vice President Richard M. Nixon, Herter worked well with the formidable secretary, John Foster Dulles, who died of cancer in May 1959 and designated Herter as his successor. Although Herter soon won President Dwight Eisenhower's confidence, his influence never approached that of Dulles. As relations with Cuba deteriorated after Fidel Castro took power in 1959, Herter counseled restraint but persuaded the Organization of American States (OAS) to pass a censure resolution against Castro.
Herter's most crucial efforts involved Soviet-American relations. Seeking to resolve the crisis that began in November 1958 when Soviet leader Nikita Khrushchev demanded that Western forces leave West Berlin, at a summer 1959 Geneva conference Herter unsuccessfully put forward proposals to unite both Berlin and eventually Germany under democratically elected governments. Efforts in 1960 to negotiate a Soviet-American arms control and reduction agreement proved equally fruitless, foundering on inspection provisions. When Soviet antiaircraft batteries downed an American U-2 spy plane on 1 May 1960 and the Soviets captured pilot Francis Gary Powers, Herter recommended that Eisenhower accept responsibility for the flights and publicly defended the missions. Khrushchev nonetheless aborted the impending May 1960 summit meeting between himself, Eisenhower, and British Prime Minister Harold Macmillan.
When President John F. Kennedy took office in 1961, Herter retired from public life. In November 1962 Kennedy appointed Herter his chief foreign trade negotiator, a post he retained until his death in Washington, D.C., on 30 December 1966.
Lemelin, Bernard. "An Internationalist Republican in a Time of Waning Bipartisanship: Congressman Christian A. Herter of Massachusetts and the Point Four Program, 1949–1950." New England Journal of History 58(1) (Spring 2001): 61–90.; Noble, G. Bernard. Christian Herter. New York: Cooper Square, 1970.