Sieun
Award-winning child actor, former JYP trainee, and the voice that can make a STAYC chorus feel like it just found its spine.
Early life and training
Sieun is the daughter of veteran singer Park Nam-jung and appeared on television with her family from childhood. She began acting professionally with Pluto Secret Society in 2014, then built a real child-actor résumé rather than collecting one cameo for a profile paragraph.
Her drama work includes Six Flying Dragons, Signal, Still 17, The Crowned Clown, and Mystic Pop-up Bar. She won Best Young Actress at the 2018 SBS Drama Awards for Still 17. She also trained at JYP Entertainment before moving to High Up and committing fully to STAYC’s debut.
Career
Sieun entered STAYC with more public recognition than the other members, which could have turned the group into “that actor’s idol project.” It did not, because her vocals immediately justified the career pivot. She became central to the group’s live reputation and often handles climactic melodic lines.
She debuted with STAYC on November 12, 2020 through “SO BAD” from Star To A Young Culture. The group’s early run—“ASAP,” “STEREOTYPE,” and “RUN2U”—turned distinct live vocal colors into the brand, while later releases let each member stretch beyond the original teen-fresh frame.
Skills and stage identity
Her voice is bright, focused, and emotionally direct. She can cut through dense synth production without simply getting louder, which is why producers repeatedly trust her with pre-choruses and chorus openings.
The acting background shows in small camera choices: she knows exactly when a lyric needs softness, alarm, or confidence. She is also comfortable speaking in international settings and has repeatedly helped bridge communication during overseas schedules.
Era map: where to start watching
- SO BAD: The public realizes the child actor did not come to idol life as a hobby.
- STEREOTYPE: One of the clearest showcases of her bright tone and emotional precision.
- RUN2U: Her chorus delivery turns reckless love into a command.
- YOUNG LUV: The vocal drama gets room to breathe outside title-track choreography.
Current era: The 2026 2:LOVE era finds her balancing STAYC’s bright identity with the authority of someone six years into the job.
Fandom file
“Park can do everything Sieun” is not subtle, but it fits. Fans also love the gap between her perfectionist work mode and the clumsy, goofy version that appears when the schedule stops demanding competence.
Do not reduce her to: “Park Nam-jung’s daughter” or “the actress.” Both are true background facts; neither explains the singer she became.
Official links
High Up’s current profile does not list a separate verified personal social account for Sieun. Her official updates run through STAYC Instagram, STAYC X, YouTube, and Weverse. I am not linking fan accounts and pretending they are hers.