Palmer was vigorous in pursuing Confederate General John Bell Hood after the Battle of Nashville in 1864. On March 9, 1865, President Abraham Lincoln nominated Palmer for appointment to the brevet grade of brigadier general of volunteers at the age of 28, with the U.S. Senate confirming the appointment on March 10, 1865. On March 16 he was promoted to command of the 1st Brigade of the Cavalry Division, District of East Tennessee, consisting of the 15th Pennsylvania, the 10th Michigan, and the 12th Ohio Cavalry Regiments. A month later he assumed command of the division after General Alvan C. Gillem was promoted to command of the District of East Tennessee. Palmer was in the vanguard of Union General George Stoneman’s raid into Virginia and North Carolina in the last two months of the Civil War. At Martinsville, Virginia on April 8, 1865 Palmer's cavalry defeated a Confederate force of Cavalry commanded by Colonel James Wheeler, the cousin of Confederate Cavalry commander Fighting Joe Wheeler. If Palmer had pushed on to Danville, only 20 miles to the north, he might very well have captured Jefferson Davis, who up till then had not left the capital of the Confederacy. Davis subsequently left the next day, upon receiving word of Lee's surrender. This was a little-known campaign immortalized in The Band's epic, "The Night They Drove Old Dixie Down".