Seonghyeon (성현)

Seonghyeon was born on January 13, 2009, in Seo-gu, Daejeon, South Korea, and grew up with a younger sister. His family later relocated to Seoul during his elementary school years, so he transferred from Daejeon Gwanjeo Elementary School to Seoul Samjeon Elementary School. He eventually left BaeMyeong Middle School and instead completed both his middle school and high school education through equivalency exams — a path many young trainees take when their schedules can’t accommodate regular schooling.

His journey into entertainment started almost by accident. He was scouted by a BIGHIT Music casting agent at Lotte World, an amusement park, when he was just a kid — the scout reportedly asked to take his photo and handed him a business card. Around the same time, in 2018, attending a J-Hope concert left a strong impression on him, and watching large-scale stage production made him want to perform himself. He officially signed with BIGHIT Music in 2021, beginning a five-year trainee period that started when he was around 13 years old (Korean age).

During those years as a trainee, Seonghyeon developed a strong creative streak, reportedly working on around 100 demo tracks before debut. This dedication paid off, since he ended up contributing to all five songs on CORTIS’s debut EP, Color Outside the Lines, and even helped with choreography for the song “GO!”

CORTIS — whose name is an acronym derived from “Color Outside the Lines” — debuted on August 18, 2025, with the digital single “What You Want.” The five-member group (Martin, James, Juhoon, Seonghyeon, and Keonho) was marketed by BIGHIT Music as a “next-generation creator crew,” emphasizing that members write, compose, choreograph, and help direct their own visuals rather than working purely as performers. As BIGHIT’s third boy group after BTS and TOMORROW X TOGETHER, CORTIS carried heavy expectations — and quickly delivered, breaking first-week sales records among 2025 debut acts and landing the EP at No. 15 on the Billboard 200.

Within his group, Seonghyeon doesn’t hold one single “fixed” position. Instead, he’s known for his songwriting input, his rapping and vocal contributions, and his eye for style — members and staff alike have noted that his fashion, music taste, and dance sensibility give him a particularly distinct identity within the group. He has a left-handed dominant hand, a shoe size of 270mm, and once performed on stage with an injured left finger, wearing a protector rather than sitting the show out.

Outside of music, Seonghyeon enjoys watching movies and dramas, playing basketball, skateboarding, and cycling. He’s a self-described cat-and-dog person, dislikes mint chocolate, and loves acai bowls and blueberries. He has a knack for mimicry — his party trick is imitating actor Han Suk-kyu’s voice — and according to his groupmates, he’s the best at grilling meat and cooking instant ramen, earning him the nickname “eomma” (mom) among other playful ones like “eomji” and “eomsal.”

In 2026, CORTIS continued building momentum with their second EP, GREENGREEN (released May 4, 2026), led by the title track “REDRED.” Seonghyeon contributed writing and composing credits to several tracks on this EP as well, continuing his role as one of the group’s creative anchors.