When he could not stir up any interest in France, he sent his drawings to magazines in the United States, where Horizon, Esquire, and The New Yorker published them. Later, Fortune and Atlantic Monthly would also publish his drawings, and his work would grace the cover of Time magazine four times.
A versatile artist, Folon designed posters for humanitarian organizations such as UNICEF, Greenpeace, and Amnesty International; illustrated works by Lewis Carroll, Ray Bradbury, and Franz Kafka; designed costumes and sets for major opera and theater productions; and in his later years, focused on sculpture. In 2000, he established the Fondation Folon on the estate of the Castle of La Hulpe, near where he grew up. More than 300 of his works are on permanent display there. Folon died in Monaco in 2005 at the age of 71.