He was born in Don Talad in 1911, the eldest son of Prince Ratsadanay, Prince of Champassak by his fourth wife, Princess Sudhi Saramuni. He was educated at Wat Liep Monastery Sch. and l'École de Droit, Vientiane. He met Mom Bouaphanh Soumpholpakdy of Kengkok and married in 1943. The couple had six sons and three daughters: Prince Keo Champhonesak na Champassak, Prince Saysanasak na Champassak, Prince Keo Halusak na Champassak, Prince Simoungkhounsak na Champassak, Prince Vannahsak na Champassak, Prince Vongdasak na Champassak, Princess Ninhdasak na Champassak, Princess Keosondarasak na Champassak and Princess Keomanisak na Champassak. He has 11 grandchildren. He succeeded on the death of his father as Head of the Princely House of Champassak, June 1946. in the same time, he renounced his rights in order to establish a unified kingdom, the Kingdom of Laos, on 27 August 1946. He then later became President of the Royal Council in 1948. In 1949, he was appointed as Inspector-General of the Kingdom.
Sympathetic to the French in Laos, he commanded a force of 15,000 that fought Japanese troops and the Lao Issara in the south of Laos. Titular leader of the royalist faction, he served as Prime Minister of the Kingdom of Laos in 1948 – 1950 and again in 1960 – 1962 when The National Assembly installed him by unanimous vote.
He retired from politics to pursue business interests from his base in Pakse and Champassak but continued to be a major power broker until his exile in 1975, the year the communist Pathet Lao came to power. In 1975 he went to France for medical treatment and never returned to Laos. He died in Boulogne-Billancourt, France in 1980 and his ashes are buried at the Cimetiere de Trivaux in Meudon France, next to his wife Princess Bouaphanh na Champassak (1920–2013).