This article presents a biographical investigation of Ki-Yong Nam, revealing a little-known story of a Korean marathon runner who lost the opportunity to compete in the canceled 1940 Olympics under Japanese colonial rule. During the Japanese colonial and postcolonial eras, Korean marathoners produced world-class performances in elite events including the Olympic Games and Boston Marathon. Their achievements served as an inspiration to ethnic Koreans during Japanese colonial rule. Today, many Koreans remember these athletes as sport activists and heroes. However, athletes who endeavored to express Korean ethnic identity received scant attention during the war period. This article explores a significant individual whose experiences and ethnic identity were largely erased from history due to the Second Sino-Japanese War and World War II, while also illuminating his life after athletics as a coach and physical education teacher in postcolonial South Korea.