 Uncles was born on September 18, 1898 in Chillicothe, Missouri.His family moved to Kansas City when he was six, and he was educated at St. Vincent's parochial school and De La Salle Academy, graduating with special honors in 1916 and receiving the Bishop's medal for finishing with first honors in the literary-scientific course.After graduation, he joined the Missouri National Guard, enlisting a few days following the declaration of war for World War I. Uncles was assigned to the unit which was federalized as Battery D, 129th Field Artillery, and he served in France under battery commander Harry S. Truman.