Isaacson began his career in 1940 as an assistant to the commercial counsellor at
Rio de Janeiro, and was appointed an attaché in 1943. Having served as commercial secretary there from 1944, he was accepted into the Foreign Service in 1946. After leaving Rio de Janeiro in 1947, he was transferred to
Bucharest at the beginning of 1948. He was then appointed counsellor (commercial) at
Athens in late 1948, and at
Washington in 1952. Having been promoted to minister (commercial), he was posted to
Paris in 1955, and acted as chargé d’affaires there in 1956 and 1958. when he was appointed chief foreign adviser to the U.K. delegation to the
United Nations Conference on Trade and Development. Later that year, he was appointed ambassador to Switzerland, a post he held until his retirement in 1968. == Personal life and death ==