Ba Nyein was already a champion boxer by the age of 13, having won Burma’s National School Cup Championship in 1936. After a break during World War II, he resumed his training and began competing internationally for Burma. He was selected to represent his country in the featherweight event at the 1952 Summer Olympics after defeating India’s Benoy Bose in a 1951 India-Burma tournament, the latter country’s only victory in the series. At the Games he was eliminated in the first round by Lech Drogosz of Poland. He retired as an active competitor in 1956 and became an officially licensed referee with the International Boxing Association, in addition to his position as a trainer with the National Fitness Council, to which he had been appointed in 1954. He trained many boxers at his Golden Tiger Boxing Club and pioneered lethwei, an unarmed Burmese martial art, by formalizing a set of modern rules and regulations and organizing national and international competitions. Outside of boxing he was a painter and a Kyar-Hto champion (a Burmese version of draughts), as well as a sports journalist and author. He died in 1979 after a struggle with colon cancer.
Myanmar