Preston enlisted in Somerville, TN in 1861 with his master, Fernando Thomas Scott, as a MS Partisan Ranger. When Fernando deserted after 6 mths, Preston stayed on. The Partisan Rangers were under the Command of Van Dorn and when he was killed, Forrest took over his men. Preston was a Quartermaster and said that he "was one of the(sic) importantest men in the Army". Forrest trusted him with money so that he could procure supplies and served the entire time. He also received a Southern Cross of Honor from the UDC.