Park Sung-hoon (born February 18, 1985), is a South Korean actor. He started his acting career with a small role in the film A Frozen Flower (2008). He became known through the plays Rooftop Room Cat, The History Boys, and Model Students. Park began to attract attention with supporting roles in SBS' Three Days (2014), Six Flying Dragons (2015–2016) and Don't Dare to Dream (2016). It was through the film Gonjiam: Haunted Asylum (2018) and KBS 2TV's My Only One (2018–2019) that he garnered more popularity. He stepped up as a leading role in the KBS2 Wednesday-Thursday drama series Memorials. Park is better known in recent years for his villainous roles in the dramas The Glory (2022–2023) and Queen of Tears (2024), as well as playing the transgender ex-soldier Cho Hyun-ju in season 2 (2024) and season 3 (2025) of Netflix drama Squid Game.