Historical records list his birth year as 1910, 1913, 1915, or 1917, though 1915 remains the most probable date. He was born in the village of Kuma-Dizi within the Mayombe district of Bas-Congo.
His father volunteered for a poison test using a substance extracted from a kasa tree to assuage hostility from local villagers regarding his wealth. The word Kasa attached itself to his name as a permanent commemoration of that event.
Joseph Kasa-Vubu's ABAKO party received 9.47% of the national vote for the Chamber of Deputies and won only 12 seats. He forged an unlikely coalition with Patrice Lumumba which led to his indirect election as President of the Republic in the Senate and the National Assembly in 1960.
On September 5th Kasa-Vubu dissolved Lumumba's democratically elected government accusing him without foundation of communist sympathies. This action provoked a political crisis that lasted until September 14th when he requested army commander Joseph-Désiré Mobutu seize power.
Mobutu seized power for a second time on the 25th of November 1965 now deposing Kasa-Vubu and placing him under house arrest. Joseph Kasa-Vubu died in a hospital in Boma four years later in 1969 possibly after a long illness.