 Bettwy was in the first class of the University of Arizona law school (the James E. Rogers College of Law) when it opened in 1915, but he interrupted his studies to join the U.S. Army.From 1916 to 1919, he participated in the Pancho Villa Expedition, including the Battle of Ambos Nogales, which was dedicated to the pursuit of Pancho Villa along the border.While stationed in Nogales, he met his bride-to-be, Mary Chenoweth Escalante, and they had their first son William in 1918.