Vietnam War Medal of Honor Recipient. He received the award posthumously (presented to his family) from Vice President Spiro T. Agnew at the White House on April 20, 1970 for his actions as a Private First Class (Rifleman) with Company A, 1st Reconnaissance Battalion, 1st Marine Division (Rein.) Fleet Marine Forces, near An Hoa Combat Base, Quang Nam Province, South Vietnam, on March 5, 1968. He joined to U.S. Marine Corps Reserve, in March 1967, and switched to active duty four months later. Following his combat and basic infantry training, he was sent to South Vietnam in January 1968, Two months later, during Operation Rock, his patrol was attacked by a platoon-sized enemy force on Hill 146 in the Quan Duc Duc Valley. When a hand grenade landed in the foxhole that he shared with fellow Marines, he yelled a warning and immediately hurled his body over the explosive charge. Absorbing the full impact of the blast, he was killed instantly. He was also awarded the Purple Heart. The Ralph H. Johnson Veterans Administration Medical Center in Charleston, South Carolina, was renamed in his honor and the US Navy guided missile destroyer USS Ralph Johnson (DDG-114) was also named in his honor. 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 Reconnaissance Scout with Company A, in action against the North Vietnamese Army and Viet Cong forces. In the early morning hours during Operation Rock, PFC Johnson was a member of a 15-man reconnaissance patrol manning an observation post on Hill 146 overlooking the Quan Duc Valley deep in enemy-controlled territory. They were attacked by a platoon-size hostile force employing automatic weapons, satchel charges, and hand grenades. Suddenly, a hand grenade landed in the three-man fighting hole occupied by PFC Johnson and two fellow marines. Realizing the inherent danger to his two comrades, he shouted a warning and unhesitatingly hurled himself on the explosive device. When the grenade exploded, PFC Johnson absorbed the tremendous impact of the blast and was killed instantly. His prompt and heroic act saved the life of one marine at the cost of his life and undoubtedly prevented the enemy from penetrating his sector of the patrol's perimeter. PFC Johnson's courage, inspiring valor, and selfless devotion to duty were in keeping with the highest traditions of the Marine Corps and the U.S. Naval Service. He gallantly gave his life for his country." He is honored on the Vietnam Veteran's Memorial in Washington DC; name inscribed at VVM Wall, Panel 43e, Line 8 (see Find a Grave Memorial 238321298).