William J. Carson (August 30, 1840 – December 13, 1913) was a United States Army soldier and the first recipient in the 15th Infantry of the United States military's highest decoration, the Medal of Honor, for his actions at the Battle of Chickamauga in the American Civil War.

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. While in the retreat across an open field and under fire, Carson helped a wounded comrade from the battlefield, which saved him from probable death on the field or capture.

On both days of the Battle of Chickamauga, on his own initiative, Carson played a key role in rallying the Union troops under heavy attack near the end of the Union line. These actions delayed further Confederate attacks long enough on the first day for the broken Union regiments to regroup and hold their ground. On the second day of the battle, the extra time gained by the troops rallied by Carson's actions allowed most of the Union Army to retreat to the defenses of Chattanooga, Tennessee without pursuit by the Confederates. Carson's actions rallied the troops and gave the impression that a large number of Union reinforcements were arriving. Renewed Confederate assaults were delayed so the Confederates could mass their forces against the supposed reinforced Union line. This delay allowed most of the Union Army on the field, including most of the XIV Corps to which the regulars were assigned, to retreat to a more secure position at Chattanooga. The small remaining rear guard force, including Carson, held the Union line for three additional critical hours until most of the remaining defenders ran out of ammunition and were taken prisoner.

William J Carson