He became an active revolutionary while studying in the Indochinese capital of Hanoi (now the capital of Vietnam) during the 1940s. The Lao People’s Liberation Army (LPLA) was established by Kaysone Phomvihane on January 20, 1949. He was minister of defence of Resistance Government (of the Neo Lao Issara) from 1950. In 1955 he was instrumental in setting up the LPRP at Sam Neua in northern Laos, and subsequently served as the Pathet Lao leader. For several years, he mostly stayed in the background, with “Red Prince” Souphanouvong serving as the Pathet Lao’s figurehead. In the years which followed, he led communist forces against the Kingdom of Laos and U.S. forces.

Kaysone came out of the shadows in December 1975, shortly after the Pathet Lao took Vientiane and effectively seized control of the country. At a “National Conference of People’s Representatives” that opened on December 1, Kaysone read a “political report” on abolishing the monarchy and declaring Laos a republic. The following day, on a motion by presiding officer Kaysone, the National Conference accepted King Sisavang Vatthana’s abdication, abolished the monarchy, and proclaimed the Lao People’s Democratic Republic. Kaysone nominated Souphanouvong as first president, and Kaysone was named prime minister. He held that post until becoming president in 1991, a post he held until his death in 1992. He married Thongvinh Phomvihane.

Under Kaysone’s watch, the process of demarcating the border between Laos and Vietnam started in 1977 and finished in 2007. According to western journalist the Lao/Viet borderline is “very close” to the 1945 border between Laos and Tonkin and Annam, respectively.

His younger son, Sanyahak Phomvihane, was elected to the LPRP Central Committee at the 8th LPRP Congress and became a Major General at the age of 40 in 2008. However, he suffered an early death, at the age of 45, on 19 July 2013. His elder son, Xaysomphone Phomvihane (born 10 October 1954) currently serves as President of the Lao Front for National Construction. His other son, Santiphap Phomvihane currently serves as Governor of Savannakhet Province.

In 2012 his cremated ashes were transferred from their original resting place to the newly built National Cemetery.