 Toon was the ambassador to Czechoslovakia from 1969 to 1971, Yugoslavia from 1971 to 1975, Israel from 1975 to 1976, and the Soviet Union from 1977 to 1979.He participated in SALT II talks from 1977 to 1979 and the American-Soviet Summit in Vienna in 1979.At the summit, Toon learned that President Jimmy Carter had chosen Thomas Watson Jr., a business executive, as his replacement, leading Toon to publicly criticized making ambassadors out of those without any State Department experience.