With additional reinforcements arriving Major King, as senior officer present, was assigned to command all regular forces in the brigade; in December already made up of 13 companies from the 15th, 16th and 19th regiments. By late February 1862 the detachment had been enlarged by another 6 companies as well as Battery H, 5th U.S. Artillery Regiment. Then King led the 844 infantrymen into the Battle of Shiloh, the battery being separated and fighting on another part of the battlefield. Shortly after the battle command of the, again enlarged, Regular Detachment developed on Lt. Col. Oliver L. Shepherd and King returned to his regiment. He led it in the Siege of Corinth and the Kentucky Campaign. When Maj. Gen. William Rosecrans took command of the new Army of the Cumberland, he took King and his battalion as his headquarters guard and personal escort; but returned them to the detachment when he formed the Regular Brigade in December.