John André was born in London to a Swiss father and French mother. He attended the University of Geneva, and in 1771, purchased a commission as a second lieutenant in the Royal Welsh Fusiliers.
In 1774, he was assigned to Canada and in the following year was present at the siege of St. Johns during the American invasion under Richard Montgomery. André was taken prisoner and transported to Lancaster, Pennsylvania, where he and other officers were routinely pelted with filth by their captors. This treatment kindled within André a deep-seated hatred of the rebels.
In 1776, André rejoined the British in a prisoner exchange. He counseled General William Howe on American military matters and also became a fixture in Loyalist social circles. His charm, skill with languages, drawing ability and poetry made him immensely popular. He was promoted to captain in the 26th Foot on January 18, 1777, and to major in 1778, and served under General Charles Grey, the British commander at the so-called Paoli Massacre of September 1777. André developed a reputation for bravery and ruthlessness, a stark contrast to the man who also designed gowns and coiffures for Tory socialites.
In 1778, Major André was named adjutant-general and joined the staff of Henry Clinton, Howe's successor. The following spring, André became the chief intelligence officer for the British and soon opened communications with Benedict Arnold, perhaps the patriots' most talented military leader, and the commandant of the fort at West Point.
On September 23, 1780, André was arrested near Tarrytown, New York, by Americans who have been variously described as militiamen or highwaymen. André was taken to George Washingtons camp at Tappan, where it was discovered that papers carried in his boot were detailed plans of West Point and the minutes from a recent meeting between Washington and his officers. These documents had been secured two days earlier from Arnold, who had agreed to turn over the fort to the British in return for a payment of ?20,000.
Unfortunately for Major André, he was returning from his meeting with Arnold in civilian clothes and under the pseudonym of John Anderson when he was apprehended. After his true identity was quickly determined, he was brought before a military tribunal on charges of spying, since he had not been in uniform. André was found guilty and sentenced to be hanged.
Alexander Hamilton and other American officers urged a prisoner exchange or other means to spare Andrés life. A direct exchange of André for Arnold was rejected by Clinton. As his fate became clear, André appealed in writing to Washington, asking that he be shot as a gentleman rather than hanged as a spy. Memories of the earlier hanging of Nathan Hale made that request impossible to honor. On October 2, 1780, displaying great composure to the end, Major John André was hanged.