Clancy enlisted as the Captain of Company B on 8/1/62. On 2/1/63, he was transferred from Company B to the Field & Staff of the Regt by reason of promotion to the rank of Lieutenant Colonel. He was captured at the battle of Peach Tree Creek on 7/19/64 and sent to the prison at Macon, GA as a POW. He was later exchanged and promoted to the rank of Colonel on 5/31/65, though he was never officially mustered in at that rank. He was mustered out with the regiment at Washington, DC on 6/3/65.