Career
He also served in the American Revolution in the Continental Army. John Keyes was commissioned as a lieutenant in Knowlton"s Rangers in 1776 by the unit"s namesake, Colonel Thomas Knowlton. Under Knowlton, he fought in the American Revolution.
He was present at the Battle of Harlem Heights, where Knowlton fell in battle.
After the war, Keyes was promoted to brigadier major and was appointed as the first adjutant general of the State of Connecticut the following year. The position was officially established by Connecticut law in 1784, and he held the office until 1791.