 Yun Dong-Ju was the eldest son among the four children of his father Yun Yeong-Seok and his mother Kim Yong.As a child, he was called "Haehwan" (해환, 海煥 ).He entered Eunjin Middle School in Longjing in 1932 and returned to Korea to attend Soongsil Middle School in Pyeongyang in 1936.