Having joined the Virginia National Guard in 1931 and served on its rifle team, McIlhenny transferred to the U.S. Marine Corps Reserve in 1935, attended Platoon Leaders Class, and served as captain of the U.S. Marine Corps Reserve rifle team.

Called to active duty when the United States became involved in World War II, McIlhenny spent 31 months in the western Pacific as a member of B Company, 1st Battalion, 5th Marines, 1st Marine Division.
 At Guadalcanal, he received the Navy Cross, the Silver Star, and the Purple Heart.
 He also saw action at New Britain and at Peleliu, where he received a second Purple Heart.

Upon retirement from the Marine Corps Reserve, McIlhenny received a promotion to brigadier general.

McIlhenny's combat helmet, along with the captured Japanese samurai sword that dented it, are on display at the National World War II Museum (formerly the National D-Day Museum) in New Orleans, Louisiana.
Having joined the Virginia National Guard in 1931 and served on its rifle team, McIlhenny transferred to the U.S. Marine Corps Reserve in 1935, attended Platoon Leaders Class, and served as captain of the U.S. Marine Corps Reserve rifle team.
Called to active duty when the United States became involved in World War II, McIlhenny spent 31 months in the western Pacific as a member of B Company, 1st Battalion, 5th Marines, 1st Marine Division.  At Guadalcanal, he received the Navy Cross, the Silver Star, and the Purple Heart.  He also saw action at New Britain and at Peleliu, where he received a second Purple Heart.
Upon retirement from the Marine Corps Reserve, McIlhenny received a promotion to brigadier general.
McIlhenny's combat helmet, along with the captured Japanese samurai sword that dented it, are on display at the National World War II Museum (formerly the National D-Day Museum) in New Orleans, Louisiana.
Walter Stauffer McIlhenny