Pelham resigned from the U.S. Military Academy at West Point in 1861, just a few weeks before he was to graduate, in order to return to Alabama and enter the Confederate Army. After a brief period of drilling an artillery battery Pelham took part in the First Battle of Manassas, so distinguishing himself that General J. E. B. Stuart recommended he form and lead a six-gun battery of horse artillery to move with the cavalry. In more than 60 battles Pelham displayed genius for sizing up the situation at a glance, dashing to a spot that commanded the battlefield but that was not vulnerable to enemy fire, and bravely raining shot and canister on forces that greatly outnumbered his own. Pelham's greatest battle was at Fredericksburg where he confused a federal army of 120,000 men with his brilliant one-gun barrage from their flank. His contribution to the Confederate victory that day was a major one and General Robert E. Lee cited the part played by "the gallant Pelham" in his official report.

Pelham, then a major, was killed at the age of 24 in the Battle of Kelly's Ford. He died in the explosion of an enemy shell, and as Stuart said, "with the battle-cry upon his lips and the light of victory beaming from his eye."

Sources:
Alabama Hall of Fame, 1968