Sent to America in 1774, André became chief intelligence officer to the British commander in chief, General Sir Henry Clinton (Clinton, Sir Henry), in New York City. From May 1779 he carried on a secret correspondence with Arnold, who had become disillusioned with the American cause. In August 1780 Arnold was appointed commandant of the fort at West Point, New York, which, at a meeting with André on September 21, he agreed to surrender for £20,000.

While returning to New York City, André was captured by three American militiamen; he failed to use the pass that Arnold had given him, and papers concerning West Point were found in one of his boots. A board of officers designated by General George Washington (Washington, George) found him guilty of spying and condemned him to death. When General Clinton refused to exchange him for Arnold, who had escaped to British territory, André was hanged. He was mourned on both sides because of his personal charm and literary talent.