Transferred to Mississippi in early 1863, Featherston assumed command of a brigade of Mississippians in Major General William W. Loring's Division in the army of General Joseph E. Johnston. Featherston's brigade was at the Battle of Champion Hill. As with the rest of Loring's division, which had marched off on its own to join Joseph E. Johnston in Jackson rather than retreat towards Vicksburg. Consequently it was not with Lieutenant General John C. Pemberton's main force at Vicksburg and was not surrendered with it. Besides the Vicksburg Campaign, Featherston fought in other major campaigns in the Western Theater of the American Civil War, including the Atlanta Campaign in 1864. Loring's men accompanied the Army of Tennessee during John Bell Hood's Franklin–Nashville Campaign, or Tennessee Campaign.