Forbes served as the American consul in
Copenhagen,
Hamburg and
Stettin from 1801 to 1819. He owned the country house America outside Copenhagen and constructed an American-style windmill known as
America Mill at the site in 1814. He served as the Chargé d'Affaires to the Republic of Buenos Aires (later
United States Ambassador to Argentina) from 1825 to 1831. ==Later career==