 On February 23, 1863, Long was appointed colonel of the 4th Ohio Cavalry, a regiment which recently had surrendered to the Confederate raider, Brigadier General John Hunt Morgan.Long improved the morale of the regiment and led it in the Tullahoma Campaign.He commanded the regiment's brigade, the 2nd Brigade, 2nd Division, Cavalry Corps of the Department of the Cumberland between March 1863 and August 20, 1864, including service at the Battle of Chickamauga.