Souphanouvong 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, his mother was a commoner, Mom Kham Ouane.
Nicknamed “The Red Prince”, he became the figurehead leader of the Lao People's Revolutionary Party, and upon its successful seizure of power in 1975, he 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 École Nationale des Ponts et Chaussées.