During the Civil War, the Kentish Guards enlisted as Company "H" of the 2nd Rhode Island Volunteers on 5 June 1861. They saw extensive service with the Army of the Potomac and fought in 14 major battles of the Civil War. The 2nd Rhode Island distinguished itself as one of the first units to engage at the First Battle of Bull Run and one of the last off the field covering the retreat of the Union Army, one of only three regiments to hold their ground in this battle, and again in the Battle of the Wilderness, being the last unit out. The 2nd Rhode Island was a primary focus of the television series by Ken Burns on the Civil War based on the memoirs of Elisha Hunt Rhodes. Members of the Kentish Guard in Company H served from the start of the civil war in 1861 and were present at Lee’s surrender at Appomattox Court House in 1865.
The Kentish Guards also recruited a second company from Kent County and supplied the officers for Company "H" 7th Rhode Island Volunteers on 22 May 1862. They saw service with the Army of the Potomac and Army of the Ohio.
Many members of the Kentish Guards served in other Army and Navy units formed in Rhode Island during the Civil War. Thirty-three members of the Kentish Guards made the ultimate sacrifice for their country during the war.
During "The War Between the States" the Kentish Guards enlisted as a unit,
and served as Company H of the 2nd Rhode Island Volunteer Infantry.