He enlisted in the U.S. Army on April 20, 1913, at the age of 23. He was the son of Joseph Francis Spencer Sr. and Mary Ann Spencer née Hurley. He was married to Katherine Anna Spencer née Dunlea and had four children Charles Leo Jr., Richard V., Ruth K. and Arthur C. Spencer.

He completed boot camp in June 1913 and joined the 2nd Infantry Regiment. He became a private in Company "L." His first posting was at Fort Shafter Oahu, Hawaii, whose regiment had served at the fort since 1911. His second posting was at Fort Sam Houston in Texas, where he was promoted to Sergeant.

His final posting was at Fort McIntosh in Laredo, Texas, where he was promoted to Regimental Sergeant Major of the 37th Infantry, Headquarters Company. His enlistment was nearing the end when the United States entered World War I on April 6, 1917. Charles reenlisted the same day and served through the end of the war. Charles L. Spencer was a qualified marksman.

Charles Leo Spencer Sr.