The President of the United States of America, authorized by Act of Congress July 9, 1918, takes pleasure in presenting the Silver Star to First Lieutenant (Corps of Engineers) William S. Harrison (ASN: 0-1116226), United States Army, for gallantry in action as a member of the United States Military Advisory Group to the Republic of Korea, in action against the enemy in the vicinity of Changsa-dong, Korea. On 14 September 1950, when a Republic of Korea guerrilla type battalion made an amphibious landing behind enemy lines near Changsa-dong, Lieutenant Harrison voluntarily accompanied the unit as an advisor. As the first company reached the beach, it was immediately pinned down by intense enemy fire. Without regard for his personal safety, Lieutenant Harrison assumed command of the troops and led them in a successful attack on the key terrain feature overlooking the beach. After receiving reinforcements, the enemy opened fire on the landing craft used by the friendly force, damaging it and causing it to run aground. When the reinforced enemy launched an attack against the friendly force, Lieutenant Harrison established a defense perimeter and moved from one position to another, encouraging the men and directing their fire. Under his able leadership, the perimeter was successfully defended until additional landing craft arrived and the battalion was evacuated. The gallantry displayed by Lieutenant Harrison on this occasion reflect the highest credit upon himself and the military service.