Clarence Douglas Dillon, known as C. Douglas Dillon, was a prominent American diplomat, politician, and financier with deep Wall Street roots. Born on August 21, 1909, in Geneva, Switzerland, to American parents, he was the son of investment banker Clarence Dillon, founder of Dillon, Read & Co. He graduated from Harvard University in 1931, joined the family business, and rose to become a partner. During World War II, he served as a naval officer in the U.S. Navy. His diplomatic career began in 1953 when President Dwight D. Eisenhower appointed him U.S. Ambassador to France, a post he held until 1957. He later served as Under Secretary of State for Economic and Agricultural Affairs (1958–1959) before being appointed by President John F. Kennedy as the 57th U.S. Secretary of the Treasury in 1961, a position he retained under President Lyndon B. Johnson until 1965. As Treasury Secretary, he advocated conservative economic policies aimed at protecting the U.S. dollar's value, including support for the Bretton Woods system and efforts to combat inflation. He was a key member of the Executive Committee of the National Security Council (ExComm) during the 1962 Cuban Missile Crisis. After leaving government, he chaired the Council on Foreign Relations from 1970 to 1978. A noted art collector and philanthropist, he donated significantly to institutions like the Metropolitan Museum of Art. He remained active in finance and advisory roles until his death on January 10, 2003, in New York City.