When he was a teenager, Chun learned Judo and Karate while studying in Japan. Before the end of World War II Chun was approached by the head of the Yun Moo Kwan judo school and asked to teach karate there. He agreed, and also taught judo there.
After World War II, at the end of the Japanese occupation of Korea, Chun moved the karate classes to a new location, establishing the Yun Moo Kwan Kong So Do Bu in 1946, essentially a new branch of the judo school. During the Korean war, Chun disappeared. When the war ended and his students returned to Seoul, his students (principally Yun Kwae Byung) reopened the school under the new name Jidokwan. The name change may have been driven in part by the desire to separate the school completely from its judo origins.
Since Chun was actively involved in martial arts instruction only between 1943 and 1950 there is little information about him. Chun helped lay the foundation, however, for what was to become taekwondo. Many of his students went on to become influential taekwondo pioneers themselves.