Koo Ja-sung: Koo Ja-sung. Actor: The Secret Life of My Secretary. Koo Ja-sung was born on 22 September 1992 in South Korea. He is an actor, known for The Secret Life of My Secretary (2019), Was It Love (2020) and Sponsor (2022).
Known For: The Secret Life of My Secretary (Ki Dae-JooKi Dae-joo(as Ja-Sung Koo)), Was It Love (Oh Yeon Woo(as Ja-Sung Koo)), Sponsor (Hyeon Seung-hoon(as Ja-Sung Koo)), Knowing Bros (Self - Guest(as Ja-Sung Koo))