Bunker first worked in his father's company, National Sugar Refining Company, eventually becoming the company's president, succeeding Horace Havemeyer Sr., in 1942. He retired as an active executive in 1951 and purchased a 600-acre dairy farm in Putney, Vermont. He remained a member of the board of National Sugar until 1966. He then moved to government during the Harry S. Truman administration, when Truman appointed him ambassador to Argentina in April 1951. Next he was ambassador to Italy in February 1952. From November 1953 until November 1956 he was president of the American Red Cross. In November 1956 he was appointed ambassador to India and Nepal by Dwight D. Eisenhower, and sworn in December 1956, where he played a crucial role in the covert alliance between the two powers against China. He was replaced by John Kenneth Galbraith in 1961. During 1962 he acted as U.S. mediator in the New York Agreement over Western New Guinea. After a period back in Washington, D.C., he was made U.S. ambassador to the Organization of American States, 1964–1966. President Lyndon B. Johnson appointed him U.S. ambassador to South Vietnam, 1967–1973. Once in Saigon, he strongly supported the war efforts of Presidents Johnson and Richard Nixon, and applauded US incursions into Laos and Cambodia. Following the conclusion of the Vietnam War, Bunker headed the US team involved in the drawing up of the 1977 Torrijos-Carter Treaties. He was awarded the Presidential Medal of Freedom with Distinction twice—the first time by John F. Kennedy in 1963 and the second time by Lyndon B. Johnson in 1967. He is one of only two persons who received the award twice, and the only person to receive it both times with distinction.
Personal life
Bunker married a neighbor, Harriet Allen Butler, daughter of Ellen Mudge and George Prentiss Butler, in Yonkers, New York on April 24, 1920. Harriet had made friends with Bunkers' sister Katherine when the two girls attended Miss Porter's School in Farmington, Connecticut. They had three children, John Birkbeck, Samuel Emmet, and Ellen Mudge. She died in 1964. On January 3, 1967 he married fellow ambassador Caroline Clendening "Carol" Laise in Katmandu, Nepal. She died in 1991. Ambassador Laise was a friend of the first Mrs. Bunker. Bunker died on his dairy farm in Putney, Vermont. The funeral was attended by his good friend and neighbor former senator George Aiken and former president Richard M. Nixon. Aiken died two months later. His middle child, John Birkbeck Bunker, a first lieutenant in World War II, died of cancer at his home in Wheatland, Wyoming at age 79.
In a 1977 Doonesbury cartoon, one of the supposed terms of the Torrijos–Carter Treaties was that "We get to keep Ellsworth Bunker."
Bunker is mentioned in Allen Ginsberg's poem "September on Jessore Road", which includes the line "Where is Ambassador Bunker today? Are his Helios machine gunning children at play?"
