Kim was born in
Gochang County,
North Jeolla Province,
Joseon. He graduated from
Waseda University in Japan in 1914. From 1897, Kim Seong-su studied under Han Hak-ju. In 1904, he married Go Kwang-seok (高光錫), the daughter of Go Jeong-ju, a resident of Changpyeong in Jeollanam-do. In 1906, he spent six months learning English at the Yeonghaksuk (英學塾) in Changpyeong, where his in-laws lived, together with Song Jin-woo (宋鎭禹). In 1908, Kim Seong-su attended Geumho School (錦湖學校) in Gunsan and then enrolled in Seisoku English School in Tokyo, Japan, in October of that year. The following year, in April 1909, he transferred to the fifth grade of Kinjo Middle School in Tokyo. After graduating in 1910, he entered the preparatory course of Waseda University in April of the same year and then chose the Political Economics department, graduating in 1914. Upon returning to Korea, with the support of his stepfather Kim Gi-jung, Kim Seong-su took over the management rights of Central School in April 1915 after repaying its debts. In March 1917, he elevated Central School to a regular educational institution and assumed the position of principal. In the same year, he acquired Kyungsung Jiknyu Joint Stock Company and began a textile business. He resigned from his position as principal of Central School in March 1918 to focus on business management, but facing decline, he began the establishment of Kyungsung Spinning. Kim Seong-su participated in the early planning stages of the March 1st Movement in 1919. In October that year, he received authorization to establish Kyungsung Spinning. He continued his education with texts like the "
Zizhi Tongjian," the teachings of
Confucius and
Mencius, and
Chinese history. He also studied
Tang poetry,
Confucian philosophy, and
Neo-Confucianism. Personally, he enjoyed reading historical texts like Sima Qian's "
Records of the Grand Historian" and the "
Three Kingdoms." Although he grew up in a wealthy family, he did not indulge in luxury. == Career ==