In December 1862, Potts was promoted to lieutenant colonel and commander of the demoralized and badly depleted 32nd Ohio. He reorganized the regiment, added substantially to its ranks, and refitted it for field duty. On Christmas Day, he was elevated to the colonelcy and then led the regiment in numerous campaigns of the Army of the Tennessee in the Western Theater, including the Siege of Vicksburg and the Atlanta Campaign. At Port Gibson he was complimented for gallantry by brigade commander Brig. Gen. John D. Stevenson; and at Raymond, Jackson, and Champion Hill, he received the thanks of Maj. Gen. John A. Logan. During the fight at Champion Hill, Colonel Potts charged with his regiment and captured an eight-gun Confederate battery and half of an Alabama infantry brigade that was guarding it.