Bennett served as a lieutenant in the 1st Delaware Regiment, a unit of the Continental Army during the American Revolutionary War. He enlisted as a 17-year-old in 1775, and served throughout the war. Present at Valley Forge and the battles of Staten Island, Brandywine, Germantown, Monmouth, Camden, and Yorktown, he was wounded three times. After the disastrous Battle of Camden in August 1780, when the 1st Delaware Regiment was decimated, Lt. Bennett was sent back to Delaware to recruit. A year later, as General George Washington and the French were gathering everyone possible for the Siege of Yorktown, Bennett rejoined the army, and recalled it as follows: