Xu Shichang
Kung had two older sisters, both borne by his mother Wang Baocui. The elder, Kong Deqi (孔德齊) (b. 1915), married the youngest son of Feng Shu (馮恕), a Beijing calligrapher and founder of Beijing Electric Lamp Company, in 1932, but died as a young woman. The younger, Kong Demao (孔德懋) (b. 1917), married Ke Changfen (柯昌汾), third and youngest son of Qing dynasty historian Ke Shaomin (柯劭忞) and Wu Zhifang, daughter of Qing dynasty prose writer Wu Rulun, in 1935. Ke Shaomin's sworn brother was President Xu Shichang. Kong Demao has one daughter, Ke Lan, one son, Ke Jian, and one grandson (the son of Ke Lan), Liu Yong. She lives in mainland China and has written a book about her experiences growing up at the family estate in Qufu.