 In 1938, Uncles graduated from the Command & General Staff College, afterwards being assigned as instructor in the Department of Tactics & Communications at the Fort Sill, Oklahoma Field Artillery School, where he served until 1940.Uncles served as assistant personnel officer, G-1, in the office of the Chief of Field Artillery from 1940 to 1942.In 1942, Uncles was assigned as assistant personnel officer, G-1, at Headquarters, Army Ground Forces, where he remained until 1943.