The 88th Illinois participated in the Knoxville campaign from 28 November to 8 December 1863. Subsequently, the unit engaged in operations in East Tennessee until February 1864. The regiment was at Loudon, Tennessee, until April and at Cleveland, Tennessee, through May. The unit took part in the Atlanta campaign from May to September 1864. The 1st Brigade was commanded successively by Colonel Sherman, Brigadier General Nathan Kimball, and Colonel Emerson Opdycke. The 2nd Division was led by Brigadier General John Newton, the IV Corps was commanded successively by Major Generals Oliver Otis Howard and David S. Stanley, the Army of the Cumberland was led by Thomas, and the combined armies were directed by Major General Sherman. The brigade consisted of the same units as at Missionary Ridge, with the 28th Kentucky replacing the 22nd Indiana. The 88th Illinois fought at the Battle of Rocky Face Ridge on 8–11 May, the Battle of Resaca on 14–15 May, the Battle of Adairsville on 17 May, and the Battle of New Hope Church on 25–26 May. First Lieutenant Noah W. Rae was mortally wounded at Adairsville and died 2 June.