Once enlisted, Brown fought as a private soldier in King's Own Regiment Dragoons (Bland's Dragoons). During this battle, he had two horses killed under him. In the thick of the action, Brown witnessed the regiment's standard falling to the ground and was captured by the French. Brown attempted to dismount his horse to recover the standard, but was struck by a blow from a sabre and lost two fingers from his left hand. His horse bolted in fright to the rear of the enemy lines, where Brown subsequently caught sight of his standard in the hands of a French trooper. Brown reclaimed the standard after killing the enemy soldier, remounted a horse, secured his regiments' standard by wedging its flagstaff between himself and the saddle, and returned to his own by galloping through the massed ranks of the enemy. During this return, Brown was further wounded by the French, receiving eight sabre cuts in his face, neck and head, and lost most of his nose as a result. Brown diced with death; two musket bullets hit his back, and three passed through his headgear, one of the latter giving Brown a cut across his forehead that went down to his right eyebrow. Returning to his own company a hero, he was applauded with 'three loud Huzzas' in recognition of his valiant bravery.