Banza was born on 10 October 1932. He was the first of three sons and grew up in the heart of Gbaya territory. Banza studied In Cameroon and Congo-Brazzaville. In his twenties, he had served with the French army in the First Indochina War and had been stationed in Gabon, Morocco, Tunisia and other locations in colonial Africa. He had a similar military record to his future colleague Jean-Bédel Bokassa, who had also served in the First Indochina War and had been stationed in Africa and Europe as a radio transmissions expert. Afterward, Banza returned to the Central African Republic, where he enlisted in the armed forces. Brian Titley, author of "Dark Age: The Political Odyssey of Emperor Bokassa" described Banza as an "intelligent, ambitious, and unscrupulous" military officer.