Walter A. Crane graduated from McKinley High School in St. Louis, Missouri, in the spring of 1917. That September, he enlisted in the Machine Gun Company of the 1st Missouri Infantry Regiment, which trained at Camp Clark in Nevada, Missouri. In October 1917, the unit transferred to Camp Doniphan, Oklahoma, and was renamed the 138th Infantry Regiment. Crane remained in a machine gun unit. The regiment stayed at Camp Doniphan until April 20, 1918, and traveled overseas in mid-May, arriving in France, via England, around May 25th. While overseas, Crane saw action throughout France, and participated in the Meuse-Argonne Offensive of September and October 1918. He was promoted to corporal in January 1919, and returned to the United States in late April of that year. During his time in the military, he corresponded with Ruth Backof (b. June 1898), whom he knew from high school. She was the daughter of Otto C. and Jessie S. Backof.