In April 1861, Douglas enlisted at Harpers Ferry as a private in Company B, 2nd Virginia Volunteer Infantry Regiment which formed part of what was later to become the Stonewall Brigade. The reality of war struck home, when the Virginia forces retreated and he was among the men detailed to burn the bridge, over the Potomac at Shepherdstown, in which his father owned stock. Douglas rose through the ranks, fighting at Bull Run as a first sergeant, and commanding his company as a lieutenant at Kernstown. In the spring of 1862 he was, through the intervention of his friend Sandie Pendleton, detailed on special duty at Stonewall Jackson's headquarters. Soon after having joined Jackson's HQ, Douglas made an extraordinary ride of 103 miles, from Mount Jackson to Brandy Station, crossing the Blue Ridge Mountains in a heavy rainstorm, with orders from Stonewall to General Ewell. As a reward for his efficient fulfillment of duty, he was, the day after his return to HQ, made assistant inspector general on Jackson's staff.