Civil War Confederate Army Officer. His father was William Nelson Pendleton, a minister and future Confederate General, who settled his family in Maryland from 1844 to 1853. Educated at home and in a private school, at age 13 Alexander Pendleton enrolled in Washington College, (now Washington and Lee), at Lexington, Virginia, where his father had accepted a parish. An excellent student, he belonged to the same literary society as Thomas J. Jackson, then on the faculty of the Virginia Military Institute. Following his graduation in 1857, he taught at Washington College for two years. At that same time he enrolled at the University of Virginia to earn a Master's degree. After entering the Provisional Army of Virginia as 2nd Lieutenant in the Corps of Engineers on May 17, 1861, he left school without completing his studies. A week later he reported to Jackson, then a Colonel in the Confederate army, at Harpers Ferry. In July, Jackson requested him for his ordnance officer, and from the 19th of that month until his death he served as a capable, well-liked, and highly respected staff officer to Jackson and his successors. Historians today call him the most capable staff officer in the whole Confederate army. He enjoyed a close relationship with Jackson, whose intensely religious nature he shared. When his commission in the Virginia expired, Jackson arranged to have him appointed 1st Lieutenant in Confederate service on November 30, 1861. He served at that rank though the Shenandoah Valley Campaign of 1862, winning Jackson's approval for manning a field piece at Kernstown when he saw its gun crew killed as he returned from carrying orders to Jackson's subordinates. Again Jackson interceded on his behalf, securing for him a promotion to Captain, in June 1862. Illness kept him out of the Second Bull Run Campaign, but he returned to duty in late summer holding a temporary appointment as Assistant Adjutant General of Jackson's II Corps. Jackson depended on his ability to convey his orders clearly and concisely, in routine paperwork and under battlefield conditions. Most of Jackson's battle reports after First Bull Run were written by him, whose efficiency resulted in a promotion to Major and permanent assignment to the adjutant generalship, on December 4, 1862. The two men became almost inseparable. It was he who dressed Jackson's body for burial after his death from wounds he received at Chancellorsville, and he was one of the pallbearers at Jackson's funeral. On succeeding Jackson as commander of the II Corps, Lieutenant General Richard S. Ewell advanced him to chief of staff with the rank of Lieutenant Colonel. Lieutenant General Jubal A. Early requested him for detached duty in the Shenandoah Valley in December 1863, and again the following June. On September 22, 1864, 3 days after the Third Battle of Winchester, he received a mortal gunshot wound to the abdomen at Fisher's Hill as he tried to check an advance on the Confederate front. Buried near the battlefield, his body was later exhumed and sent to his family in Lexington, Virginia. On October 24, 1864, his parents and his wife of 9 months attended his reburial near Jackson's grave. One month later his only child, a son, was born.

According to Wiley Sword's 'Confederate Invincibility', his last words were "It is God's will; I am satisfied."