Kim You-jung: Public Face, Open Heart and a Mask

02The public face

In My Demon, Kim You-jung plays Do-hee, a CEO who built a dessert company in college and made it number one in seven years. The trailer opens with her on a stage, being named CEO of the Year. She is polished, composed, and clearly in control. In a noisy bar where her coworkers assume she is dating the new recruit, she says one line that stands out: I have a public face to uphold.

It is a romantic comedy, so the line is light. But the idea of a public face is about to come back.

03The heart that cannot hide

20th Century Girl is a 2022 Netflix film about first love and best friends. Kim You-jung plays Bo-ra, and the trailer is built on feelings that are very hard to hide: a crush, a secret, and a heart that hurts a little every time someone walks by. It is the opposite of a poker face.

04A mask worn to survive

Dear X is a 2025 TVING Original, directed by Lee Eung-bok. Kim You-jung plays Baek Ah-jin, one of the country's top actresses. On the surface she has everything: beauty, fame, and an audience that adores her. Underneath, the story says, she hides a cruel side and wears a mask to survive. This is a dark series, rated for adults, so its harshest scenes stay out of this story. What we can talk about is how she approached the part.

In June 2025, she told Cosmopolitan Korea that the role felt difficult, and that she was afraid of it at first. What helped was a conversation with the director, who explained why she was the right person for it. That talk gave her the courage to say yes. She described her method in another interview: rather than adding more to the character, she focused on emptying herself and conveying emptiness. In November she told The Korea Times that the hardest part was hiding her emotions. Instead of showing more, she tried to show less, keeping her expression restrained so that Ah-jin's intentions were hard to read.

Knowing a face is not the same as knowing the character behind it.

The teaser shows the idea at work: a press conference, a polished smile, and a calm hello, then quiet, cold close-ups with almost nothing on her face, and then she is smiling in the back of a car while the words on screen call her a devil. The same face, three different messages. A teaser is not a performance, though, and Ah-jin's mask belongs to the character, not to the actress.

05Three roles, one question

Put the three roles side by side. In My Demon, a public face to uphold. In 20th Century Girl, a heart that cannot stay hidden. In Dear X, a mask worn to survive. Each role asks a different question: what do we show, and what do we keep? These are three roles chosen to look at one idea, not a straight line from soft to dark.

06A lie told with crossed fingers

100 Days of Deception premieres on tvN on October 10, and Netflix carries it around the world. It is a period spy romance, set in 1932 Gyeongseong, which is today's Seoul, under Japanese colonial rule. Kim You-jung plays Lee Ga-kyeong, a top pickpocket who takes on a false identity and infiltrates the Japanese Government-General as an undercover spy for the independence movement. Across from her is Park Jinyoung, as an interpreter in the same building.

In the trailer, both of them are given orders that sound almost like mirror images: earn her trust, win his heart. Only the trailers have been seen, so there is no judging the performance. But the question feels familiar: what happens when a face invites you to trust it, and you cannot tell if you should? You can read more about Kim You-jung and the roles she has described.