Through Kuni Asahiko his maternal great-grandfather, Ku was a second-cousin to Emperor Emeritus Akihito of Japan.

He later attended Centre College, Danville, Kentucky[1] and studied architecture at Massachusetts Institute of Technology both in the U.S.

He married Julia Mullock (1927–2017) on 25 October 1959 at St George's Church in New York and they adopted a daughter, Eugenia Unsuk.

After the fall of Syngman Rhee, he returned to Korea in 1963 with the help of the new president Park Chung Hee, moving into the New Building of Nakseonjae hall, Changdeokgung with his mother and wife.

His funeral was held on July 24, 2005, and his posthumous title decided as "Prince Imperial Hoeun" (Korean: 회은황세손; Hanja: 懷隱皇世孫) by the Jeonju Lee Royal Family Association.