Samuel Koster graduated from the U.S. Military Academy at West Point, Class of 1942. he served from 1968 to 1970 as Superintendent of the Academy. After that billet, he was slated for promotion to lieutenant general before receiving a reduction in rank to brigadier general and retiring as a result of his efforts to minimize the details of the My Lai Massacre in Vietnam. He retired in 1973 as a U.S. Army Brigadier General.