Korean War Medal of Honor Recipient. He received the award posthumously for his actions on July 25, 1953 as a staff sergeant Company F, 2nd Battalion, 7th Marines, 1st Marine Division near Songuch-on, Korea. It was presented to his parents on his behalf by the Secretary of the Navy Charles S. Thomas, during a special ceremony in his office on August 18, 1954. He enlisted in the U.S. Marine Corps at the age of 18 and following his recruit training at San Diego, California, he was assigned to the 7th Marine Regiment. He then attended Sea School and after graduation he served a tour of duty on the USS Curtis. He then became a drill instructor at the Marine Corps Recruit Depot in San Diego. Following that assignment, he was sent to Korea where he died in combat at the age of 23 while defending a forward outpost against a large enemy attack. Ironically, his death occurred only two days before the Korean War ceasefire was declared. He also was posthumously awarded the Purple Heart. His Medal of Honor citation reads: "For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty while serving as a platoon Sergeant of Company F, Second Battalion, Seventh Marines, First Marine Division (Reinforced), in action against enemy aggressor forces in Korea on July 25, 1953. Participating in the defense of an outpost forward of the main line of resistance, Staff Sergeant GUILLEN maneuvered his platoon over unfamiliar terrain in the face of hostile fire and placed his men in fighting positions. With his unit pinned down when the outpost was attacked under cover of darkness by an estimated force of two enemy battalions supported by mortar and artillery fire, he deliberately exposed himself to the heavy barrage and attacks to direct his men in defending their positions and personally supervise the treatment and evacuation of the wounded. Inspired by his leadership, the platoon quickly rallied and engaged the enemy force in fierce hand-to-hand combat. Although critically wounded during the course of the battle, Staff Sergeant Guillen refused medical aid and continued to direct his men throughout the remainder of the engagement until the enemy was defeated and thrown into disorderly retreat. Succumbing to his wounds within a few hours, Staff Sergeant GUILLEN, by his outstanding courage and indomitable fighting spirit, was directly responsible for the success of his platoon in repelling a numerically superior enemy force. His personal valor reflects the highest credit upon himself and enhances the finest traditions of the United States Naval Service. He gallantly gave his life for his country."