ung Yong-joo (정용주; born July 27, 1996) is a versatile South Korean actor known for his compelling character transformations across a wide spectrum of genres, from youth dramas to historical comedy and noir.

He began expanding his career into film and streaming, quickly establishing him as a "hidden gem" due to his stable acting tone and exceptional ability to completely dissolve into distinct roles. He is highly praised for his dynamic range and the captivating sense of realism he brings to his characters. He showcased his talent for lighthearted, unique portrayals in the youth drama The History of Dorks and the historical comedy Flower That Blooms at Night (2024), where he played the loyal, yet humorously clumsy, military officer Bi-chan. His performance as Ryu Han-woo in Motel California (2025) was particularly noted for his natural, witty use of improvisation, earning him a reputation as a "laugh-maker." Demonstrating his darker side, Jung delivered a chilling performance as the prisoner Kim Ji-young in the hit series Death's Game (2023). Critics highlighted his stunning visual transformation, shifting seamlessly from a seemingly innocent demeanor to a cold, murderous glare, providing one of the series' most shocking twists. His dramatic work extends to independent cinema, where his performance as the desperate victim Nam Jin in the short film Intercession earned him an invitation to the Arizona International Film Festival. He was praised for his immersive expression of the character's despair, pain, and fear. He continues to build a strong presence in the industry, including his role as Hyun-guk in the Netflix series You and Everything Else (2025), consistently enriching projects with his realistic character interpretation and solidifying his position as a highly anticipated talent.