Cheysson was born in Paris and attended the Cours Hattemer, a private school.[2] He fled from France during World War II and joined the 2nd Armored Division of General Leclerc, serving as a second lieutenant in the 12th Chasseurs d'Afrique Regiment. He joined the Foreign Ministry in 1948 and became head of the liaison service with the West German authorities the following year. As he moved through the ranks of the Foreign Ministry, he served as counselor to the president of the government of French Indochina in 1952, cabinet chief of PremierPierre Mendès France from 1954 to 1955, and general secretary of the Commission for Technical Cooperation in Africa from 1957 to 1962. He was director of the Organisme Saharien from 1962 until 1965, and ambassador to Indonesia from 1966 to 1969.
In 1973, Cheysson was appointed as the French European Commissioner. His first post, which he held until 1977, was in charge of development policy, cooperation, budgets, and financial control. From 1977 until 1981, he took on the development portfolio.
In 1981 he left the commission and became a member of the French Government, serving as Minister of Foreign Affairs until 1984. (The ministry was renamed as the Ministry of External Relations, but the previous name was re-established in 1986.) He joined the Delors Commission, where he was responsible for Mediterranean policy and north–south relations, from 1985 to 1989.