Carson, a bugler and private in the 15th United States Infantry Regiment of the United States Regular Army, helped rally a detachment of the Regular Army Brigade (Regular Brigade) of the Union Army of the Cumberland to hold an advanced position for a critical period of time at the Battle of Stones River on December 31, 1862. The forward regiments held off a large Confederate attack long enough to permit the Union forces which were withdrawing elsewhere on the battlefield to regroup and hold critical defensive lines protecting their supply line and route of retreat over the Nashville turnpike and a railroad line. The forward regiments ultimately had to withdraw in haste in the face of superior force but then held key fallback defensive positions and held the field at the end of the battle.