At the age of 18, Yang was in Manchuria during 1938 when he was conscripted into the Kwantung Army of the Imperial Japanese Army to fight against the Soviet Union, at a time when Korea was ruled by Japan. During the Battles of Khalkhin Gol, he was captured by the Soviet Red Army and sent to alabour camp. Due to the manpower shortages of the Red Army in its fight against Nazi Germany, in 1942 he was pressed into fighting in the Soviet Red Army along with thousands of other prisoners, and was sent to the eastern front.
In 1943, he was captured by Wehrmacht soldiers in Ukraine during the Battle of Kharkov, and was then pressed into fighting for Germany. Yang was sent to France to fight in a battalion of Soviet prisoners known as the Ost Batallion, serving in a battalion located on the Cotentin peninsula inNormandy, located close to Utah Beach. After the D-Day landings in northern France by the Allied forces, Yang was captured by paratroopers of theUnited States Army in June 1944, who initially believed him to be Japanese in German uniform, and was placed in a prisoner-of-war camp in the United Kingdom. At the time, Lieutenant Robert Brewer of the 506th Parachute Infantry Regiment, 101st Airborne Division, reported that his regiment captured four Asians in German uniform after the Utah Beach landings, and that initially no one was able to communicate with them. Kyoungjong later emigrated to the United States, where he lived until he died in Illinois in 1992