Ko Sung-hee (Korean: 고성희; born June 21, 1990) is a Korean-American actress. She played her first leading role in the fantasy-period drama Diary of a Night Watchman (2014). ()
Ko Sung-hee (Hangul: 고성희; born June 21, 1990) is a South Korean actress. She is best known for her leading roles in Diary of a Night Watchman (2014) and My Holo Love (2020). She has also starred in While You Were Sleeping (2017) and Mother (2018).