Kyi Maung was a final year student in 1941 when he left university to join the Burma Independence Army to fight the British colonial government. In 1943, he was sent to Japan for officer training school, from which he graduated in 1945. Upon return, he joined No. 5 Burma Rifles. He eventually rose to the rank of Battalion Commander when he was sent to the US for further training between 1955 and 1956. He was promoted to regional commander in 1960 when he became head of Yangon Command.
