American Civil War
In the spring of 1861, he served as an aide-de-camp to General P.G.T. Beauregard and was sent by the general to demand the surrender of Fort Sumter in Charleston. After the commander of the fort, Major Robert Anderson of the U.S. Army declined to surrender, Chesnut gave orders to the nearby Fort Johnson to open fire on Fort Sumter. In consequence the first shots of the Civil War were fired, on April 12, 1861. In the summer of 1861 Chesnut also took part in the First Battle of Manassas as an aide-de-camp to Beauregard.
In 1862 Chesnut served on South Carolina's Executive Council. He introduced the motion on January 9 to create administrative departments, of which he became Chief of the Department of the Military of South Carolina. In this position, Chesnut's authority over military affairs superseded that of governor Francis Pickens. On March 5, 1862, he issued a call for recruitment which warned that South Carolina would institute conscription if the state failed to enlist 5,000 volunteers by March 20.
As military department chief, Chesnut oversaw impressment of slaves for South Carolina's war effort. Between March and July, Chesnut authorized the use of impressed slaves for Charleston's defenses and for Colonel Arthur Manigault's use at Winyah Bay. On July 28, 1862, the council approved Chesnut's proposal to implement state-wide impressment which would provide the military with three thousand hands per month for four months.
Chesnut was aware that impressed slaves would be especially vulnerable to malaria while working on defenses in the coastal region. On August 22, 1862 he wrote to the Charleston Mercury that slaveholders had "a real substantial objection" to impressment, in the form of their properties' human needs being neglected, and promised to appoint "an officer of character... to watch over and protect the negroes." However, the Charleston Daily Courier later described the state appointed overseers as even more "raw... unaccustomed" than usual, and "not seem[ing] to care" for slaves' basic needs.
Later in the war he served the Confederate Army as a colonel and an aide to Confederate President Jefferson Davis. In 1864 he was promoted to brigadier general and given command of South Carolina reserve forces until the end of the war. He was third in command of the confederate forces at the Battle of Tulifinny. He was in overall command before the arrival of Maj. Gen. Samuel Jones and later Brig. Gen. Lucius Gartrell. After the war, he returned to the practice of law in Camden and formed the Conservative Party.
