Talley first entered the military as a reserve officer in the United States Army Coast Artillery Corps in the mid-1920s. He joined the United States Army in June 1926. As a second lieutenant, Talley was stationed with the 2nd Engineer Battalion in Texas and Colorado before attending the Engineer School in Virginia. He was then involved in the Nicaragua Canal Survey and assisted in the aftermath of the 1931 Nicaragua earthquake. Talley was assigned to put out the ensuing fire after the earthquake hit Managua. When Talley returned to the United States, he worked to make maps based on aerial photographs for nine years, publishing the textbook "Photogrammetry". He also invented a 'portable stereocomparagraph' and lectured at Harvard University. He was executive officer to the district engineer based in Portland, Oregon.