McKeon was born into a very large, close family of the Catholic faith. He served in the United States Navy during World War II aboard the. He toiled in a factory before joining the Marine Corps in 1948. He mentioned how harsh the training at Parris Island was at the time. For example, he and his fellow recruits were once forced to crawl through pig manure as part of a drill. McKeon served in the Korean War for fourteen months as the leader of a machine gun squad. After the war, McKeon was selected for drill instructor training. He completed the rigorous school graduating 14th out of 55. His superiors thought him bright, hard-working and alert. The psychiatrists who examined him found no evidence of mental abnormality, but did mention he had a tendency towards acting before thinking.
Ribbon Creek incident
McKeon was assigned to Platoon 71, "A" Company, 3rd Recruit Training Battalion. On Sunday night, April 8, 1956, between 8 p.m. and 8.45 p.m., he marched 74 men of Platoon 71 from their barracks to Ribbon Creek, one of the tidal streams on Parris Island, and led the men into the water. Some of them got into depths over their heads, panic ensued, and six recruits drowned in the resulting confusion. The ill-fated march set off immediate repercussions which shook Marine Corps training from top to bottom. Moreover, an uninterrupted flood of publicity by the press, radio, and television divided the country into two camps, those who condemned McKeon for what had happened and those who sympathized with him. General Randolph McCall Pate, Commandant of the Marine Corps at the time of the incident and the time of the trial of SSgt Matthew McKeon, US Marine Corps, testified as a witness for the defense. His court-martial began at Parris Island on July 16, 1956. Retired Marine Corps icon Lieutenant General Lewis B. "Chesty" Puller testified on McKeon's behalf, though he did privately reprimand McKeon. McKeon was represented by noted defense attorneyEmile Zola Berman.
Aftermath
McKeon was acquitted on August 4, 1956, of charges of manslaughter and oppression of troops. He was found guilty of negligent homicide and drinking on duty. The sentence was a $270 fine, nine months of confinement at hard labor, rank reduced to private and a bad conduct discharge. The Secretary of the Navy later reduced the sentence to three months in the brig, reduction to private with no discharge and no fine. McKeon was transferred to a Marine base in Cherry Point, North Carolina, and attempted to rebuild his shattered career. He was forced to take a job in the enlisted men's kitchen to augment his meager pay. He eventually was discharged as a Lance Corporal in 1959 due to medical problems. McKeon lived out his life in West Boylston, Massachusetts, and made his living as an inspector of standards for the state. In 1970, he told Newsweek that he was always haunted by the Ribbon Creek tragedy and the fact that the young men who drowned would have now had families of their own. He said he prayed every day for forgiveness and to keep the boys in God's safekeeping. He was survived by his wife, five children and eight grandchildren.
