He was one of the sons of Prince Bounkhong, the last vice-king of Luang Prabang. Unlike his half-brothers Souvanna Phouma and Phetsarath, whose mothers were of royal birth, he was born to a commoner. Educated in France and Vietnam, he eventually fell under the spell of Ho Chi Minh and joined the Indochinese communist movement.
Nicknamed "The Red Prince," he became the titular leader of the Lao People's Revolutionary Party and upon its succesful seizure of power, became the first president of the Lao People's Democratic Republic.After 1986,Phoumi Vongvichit was acting president,and when strongman Kaysone Phomvihane decided to establish an executive presidency in 1991,Souphanouvong was relieved of even an inactive-figurehead role.
He is said to have been the most talented of Bounkhong's sons, mastering eight languages, including Greek and Latin. He worked on the ports of Le Havre before taking his engineering degree from the Ecole Nationale des Ponts et Chaussees.