Watson was an apprentice of John Brown, the important Providence, RI, merchant before the Revolution. He served Washington, Adams and Franklin as an emissary who could be trusted with important documents. After the war, he lived in Albany, NY, and worked to promote the western expansion of the state, with particular interest in inland navigation and canals. After another period in Europe he returned to Pittsfield, MA, in 1807. He became active in agricultural improvements, including the introduction of merino sheep and the growing county fair movement. His land development projects included several towns in New York, among them Cortland, Port Watson and Homer. After yet another visit to Europe, in 1828 he settled permanently in Port Kent, Massachussets on Lake Champlain. He wrote widely, including travel accounts, memoirs, and on various agricultural subjects.