 Clayton served as a lieutenant in Company H, while his twin brother John M. Clayton served as the First sergeant in the same Company.The 124th Regiment was under the command of Colonel Joseph W. Hawley.The 124th Regiment was in reserve during the Battle of Second Bull Run and, on September 9, 1862, became part of the Twelfth Corps of the Army of the Potomac under the command of General Joseph K. Mansfield.