Civil War Union Army Officer. Born in Philadelphia, he enlisted in the Union Army on July 9, 1861, being commissioned as Captain of Company G, 66th Pennsylvania Volunteer Infantry. The regiment failed to complete its recruitment, and was disbanded. John W. Moore was transferred on March 3, 1862 to Company K, 99th Pennsylvania Volunteer Infantry and became its Captain. The 99th Pennsylvania served most of the Spring and Summer of 1862 in the defenses of Washington, DC, not seeing their first action until the August 1862 Second Bull Run Campaign. It later fought in the December 1862 Fredericksburg Campaign, and the May 1863 Battle of Chancellorsville. Promoted to Major on February 20, 1863, John Moore was the commanding officer of the regiment as it arrived on the battle fields at Gettysburg in July 1863. Stationed around the soon to be famous Devils Den area, Major Moore was directing the placement of his regiment when he received a gunshot wound and had to be taken from the field. The unit would go on to enact a stout defense of their position, despite repeated attacks by the Confederates, losing 33 men killed in the action. Major Moore returned to his command the next day, directing it was it held its position during the failed Pickett's Charge, later directing the regiment in follow up actions supporting the II Corps. For his bravery he was recommended for a promotion. On April 10, 1864 he was commissioned as a Lieutenant Colonel, but was never mustered in at that rank. The commander of the division, Major General David B. Birney, recommended that a regiment of sharpshooters be raised. Major Moore was then tasked with raising that unit, which became the 203rd Pennsylvania Volunteer Infantry. On September 10, 1864 he was commissioned Colonel and commander of the unit. In January 1865 the regiment participated in the 2nd and successful assault on the last Confederate stronghold on the Atlantic coast – Fort Fisher in North Carolina. The combined Army-Navy attack ended with the fort capitulating. Colonel John W. Moore led his men as they charged over defensive traverses, sword in one hand and the regiment's flag in the other. After they had captured three traverses and were heading for the fourth, Colonel Moore was shot down and killed, the flag still in his hands.