In 1862, Vance was appointed Acting Assistant Adjutant General to Gen. William Rosecrans during the Tullahoma Campaign. He fought at the Battle of Farmington during the Siege of Corinth. Vance was then tasked with command of Bardstown, Kentucky from October 1862 to January 1863, defending it from a Confederate cavalry raid. In March, Vance was promoted to Assistant Inspector General of 2nd Brigade, 2nd Division, XX Corps until October. He fought with the regiment at Liberty Gap and Chickamauga, being mentioned in dispatches by Gen. William Carlin for his actions during the latter engagement. Carlin named Vance an Aide-de-Camp, where he served until July 1864. He fought with Carlin at Lookout Mountain, Missionary Ridge, Resaca, and Kennesaw Mountain.