Rumbold began his career in the Foreign Office in London and was posted to Washington, D.C., in 1937. He returned to the Foreign Office in 1942 before being posted to Italy in 1944 to the staff of the Minister Resident at Allied Headquarters in the Mediterranean, Harold Macmillan. He moved to Prague in 1947, returned to the Foreign Office again in 1949 as head of the Southern Europe department with the rank of Counsellor, and was posted to Paris in 1951 with the same rank. In March 1954 he was appointed principal private secretary to the Foreign Secretary, Anthony Eden. He accompanied Eden on several overseas visits including the Geneva Conference in May 1954, Eden and Winston Churchill's trip to Washington in June for talks with the Secretary of State and President Dwight D. Eisenhower, and a tour of European capitals in September 1954. When Churchill resigned and Eden became Prime Minister in April 1955, Rumbold remained for a few months as PPS to the new Foreign Secretary, Harold Macmillan, accompanying him to San Francisco in June 1955 for talks between the Foreign Ministers of the United States, Britain, France and Russia in preparation for the Geneva Summit in the following month. Rumbold left the Foreign Office for a time, then returned, and was an assistant Under-Secretary of State 1957–60, responsible for European and East-West relations. Again he accompanied the Foreign Secretary, now Selwyn Lloyd, in international talks including Eisenhower's visit to England in August 1959, and was British representative on working groups preparing for the frequent top-level conferences at that time, including the 1960 Paris Summit which failed because of the U-2 incident just before the summit took place. In June 1960 Rumbold was appointed Minister in Paris ; The Times suggested that he could have been appointed as ambassador in a smaller mission if he had not chosen to remain on the "inner circuit" of major capitals. In 1965 he was appointed Ambassador to Thailand; while he was there he was also UK representative on the Council of SEATO. In 1967 he received his final appointment as Ambassador to Austria. He retired from the Diplomatic Service in 1970.
Anthony Rumbold inherited the Rumbold baronetcy on the death of his father, Sir Horace Rumbold, 9th Baronet, in 1941. In 1937 he married Felicity Ann Bailey at St Margaret's, Westminster. They had three daughters and one son, who inherited the baronetcy as Sir Henry Rumbold, 11th Baronet. Anthony Rumbold's best man at his wedding was his friend and fellow-diplomat Donald Maclean who was much later revealed to be a Soviet spy, which led to suspicions that Rumbold might have been the so-called "Fifth Man" in the spy ring which included Maclean. In 1974 Sir Anthony and Lady Rumbold were divorced and he married Mrs Pauline Graham, whose first husband had been the anthropologist and ethnographerJulian Pitt-Rivers. They had no children; she died in 2008.
