Gration saw active service during the Malayan Emergency, before attending the British Army Staff College, Camberley in 1964. He completed a tour of duty during the Vietnam War between 1969 and 1970, during which time he was posted as commanding officer of the 1st Australian Civil Affairs Unit with the rank of lieutenant colonel. For his "distinguished services" in Vietnam, Gration was appointed an Officer of the Order of the British Empire in 1971.