Prince Norodom Chantaraingsey, a grandson of Norodom of Cambodia and cousin of King Norodom Suramarit, was born in 1926 in Phnom Penh. He was younger than Suramarit's son Sihanouk. He began his military career during World War II and the Japanese occupation of Cambodia, serving in the Japanese-sponsored anti-French forces under Son Ngoc Thanh. After the war's end and the resumption of colonial rule, Chantaraingsey escaped to Thailand and became one of the most prominent non-communist leaders of the Khmer Issarak, leading armed resistance in the provinces of Kompong Speu and Kompong Thom at the head of a large private militia. In 1949 he joined the Khmer National Liberation Committee, becoming its Supreme Army Chief, then from 1951 he associated himself with the forces of Son Ngoc Thanh in Siem Reap, though he continued to operate as a regional warlord, maintaining his own troops.