While serving as the Communications Officer with Communication Support Company, First Battalion, Thirteenth Marines, Ninth Marine Amphibious Brigade in connection with combat operations against the enemy in the Republic of Vietnam.  On 23 February 1969, the battalion came under a North Vietnamese Army sapper attack and several communications links were damaged by the intense enemy fire.  Reacting instantly, First Lieutenant McCarthy expeditiously restored the vital wire and radio channels and was instrumental in his unit’s repelling the hostile soldiers.  As a result of his diligent and resourceful efforts, the operational effectiveness of his unit was greatly enhanced.  By his initiative, superb professionalism and loyal devotion to duty, First Lieutenant McCarthy earned the respect of all who served with him and upheld the finest traditions of the Marine Corps and of the United States Naval Service.

The Combat Distinguishing Device is authorized.