On February 10, 1864, by order of Generals Johnston and Hardee, the four artillery battalions in Hardee's corps were officially merged into the corps artillery regiment, and Smith, still a Major, was assigned to its command. Hardee recommended his promotion to Lieutenant Colonel; and General Johnston joined in the recommendation. In May 1864 now Lieutenant Colonel Smith served in the Atlanta Campaign, including the Battle of Peachtree Creek. The campaign was disastrous for the Confederacy and the artillery. While in the retreat Smith was able to save 28 guns. His corps artillery lost about all other equipment . He continued to lead the corps artillery during the Franklin-Nashville Campaign.