It’s not uncommon for established K-pop groups to split into subunits at a certain point in their careers. Through subunits, companies and idols can mix and match their lineups based on musical preferences, aesthetics, or concepts, and even the overall synergy and personality that certain members exude when grouped together. In 2026, NCT introduced JNJM, DRIPPIN debuted its first subunit, ChaDongHyeop, and ZEROBASEONE launched its first unit, EMP. Meanwhile, SEVENTEEN continued expanding its catalogue of member-led projects, with Jeonghan and Joshua debuting as JxJ in October. But how did the subunit model begin, and what purposes does it serve?

Starting in 2006, the very first K-pop subunit debuted under SM Entertainment as Super Junior-K.R.Y., a trio of vocalists from their parent group Super Junior, consisting of Kyuhyun, Ryeowook, and Yesung. While Super Junior’s main discography was filled with mostly dance, pop, rock, and hip-hop styles at the time, K.R.Y. was a chance to cement the trio’s own identity as a ballad-focused group. As Super Junior’s main vocalists, Kyuhyun, Ryeowook and Yesung were well suited to a subunit focused on ballad music, allowing SM to showcase their vocal strengths in a different setting.

With the group debuting in November 2006 on Music Bank with “The One I Love,” and achieving major success as K-pop’s pioneering ballad unit, their popularity carried over not just in South Korea, but throughout Asia. Super Junior-K.R.Y. made its first overseas appearance at the 6th Pattaya International Music Festival in Thailand in 2007, where the event attracted more than 10,000 Thai fans across its performances. The trio later expanded its reach to Japan, where its concerts reportedly drew a combined audience of 72,000 across three cities, including 36,000 in Tokyo. These milestones demonstrated the potential for subunits to attract audiences in their own right, establishing the format as more than a one-off experiment.

However, only months after K.R.Y. debuted, SM had already mobilized to debut its second subunit, Super Junior-T, in February 2007. Consisting of members Leeteuk, Heechul, Kangin, Sungmin, Shindong, and Eunhyuk, Super Junior-T was a trot-singing group, capitalizing on the oldest form of Korean pop music. Super Junior-T’s formation reflected a broader shift in South Korea’s music scene, where trot was competing with the growing popularity of genres such as pop, hip-hop and R&B. By blending traditional trot with the appeal of an established idol group, the subunit introduced the genre to a younger audience already familiar with Super Junior, offering a fresh approach to a longstanding style of Korean popular music.

From a commercial perspective, subunits can offer a lower-risk alternative to debuting an entirely new group, as they build on an established act’s existing fanbase. They can also create additional revenue opportunities through album sales, unit-specific merchandise, concerts and fan meetings tailored to different audiences.

While Super Junior-T wouldn’t be the last unit to branch off from its parent group, other idol groups and companies followed in SM’s footsteps. Debuting under Pledis Entertainment in 2010, the trio Orange Caramel became the first subunit of the popular girl group After School. Steering away from After School’s mature, powerful, and “cool older sister” aesthetic and sound, Orange Caramel’s concepts were a complete 180, focusing on the quirky, campy, and whimsical side of K-pop for a more “younger sister” vibe. With After School members Nana, Raina, and Lizzy, Orange Caramel became a cultural phenomenon in their own right.

Their 2014 single, “Catallena,” became their most popular song for its eccentric mermaid-themed, food-inspired music video, paired with its catchy disco-pop sound. Although few subunits achieve the same level of recognition as their parent groups, Orange Caramel carved out a distinct identity through bold, playful concepts and high-concept music that transformed kitsch into a creative signature.

For artists, this is one of the greatest benefits of a subunit: being able to pivot and experiment with their own musical identity and style that wouldn’t conceptually fit the main group’s image. With fewer members in the lineup, there’s more room for idols to grow and showcase their talents in ways that they couldn’t express before. This is especially true for larger groups where not everyone gets equal line distribution in a song or equal screen time in a music video or music show performance. There’s another level of artistic freedom, independence, and space that doesn’t always work in a group full of creatively different idols.

Additionally, the mid-2010s saw newer, even more refined versions of the traditional K-pop subunit. When SEVENTEEN debuted in 2015 with 13 members, its structure already incorporated three specialist teams: the vocal, hip-hop and performance units. Each focuses on a different aspect of the group’s music, allowing members to showcase their respective strengths through dedicated unit tracks and performances. For songs that require the group’s strongest singers, the vocal team (Woozi, Jeonghan, Joshua, DK, and Seungkwan) would be the main focus. Alternatively, for rap-heavy tracks, the hip-hop team (Vernon, Mingyu, S.Coups, and Wonwoo) would be deployed. And finally, for SEVENTEEN’s songs that focus on movement and dance, that’s where the performance team (Hoshi, Jun, The8, and Dino) would take the lead.

It’s one thing for subunits to gradually branch off from the parent group, but it’s another to have a built-in unit system from debut where everyone knows their roles and what they bring to the table. In SEVENTEEN’s case, it shows that they know how to shift focus based on the group’s needs, whether it be the full 13-member lineup or one of its three smaller subsets.

Meanwhile, in 2016, SM Entertainment introduced its own new take on the subunit concept with NCT. As opposed to units that debut after its main group has already established itself as an industry mainstay, the NCT brand itself was created specifically for debuting various subunits right out of the gate, marketed for specific demographics and an “unlimited” number of members overall. The first unit to debut was NCT U, with members Taeyong, Ten, Mark, Jaehyun, and Doyoung in their first single, “The 7th Sense.” Although they were the first five members to debut under the unit — with Taeil and Kun debuting in the B-side track “Without You” — NCT U was meant to establish a rotating lineup, combining different members in any given release.

Since then, seven subunits have debuted from NCT, including NCT 127, NCT Dream, WayV, NCT DoJaeJung, NCT Wish, and NCT JNJM — and currently, 23 members total. Through this market expansion, SM could cover multiple demographics and regions simultaneously, with each subunit containing its own unique musical and visual signatures and niche purpose in the K-pop market. From bubblegum pop to gritty hip-hop, electro-dance, and R&B, the NCT brand has expanded across multiple genres, concepts, and regions, including South Korea, North America, China, and Japan. 

Finally, subunits can help keep a group’s brand active during periods of reduced activity, including breaks between comebacks and military enlistment periods. As performers need time to rest between promotional cycles, subunits offer a way to maintain fan engagement and keep the group in the public eye without requiring the full lineup to remain active year-round.

Similarly, it works the same way when male idols begin to enlist in the military, and lately, SEVENTEEN has especially been making the most of this time. While BSS (BooSeokSeon) debuted in 2018 before enlistments began, the group has already debuted seven succeeding units since 2024. Each unit draws on the initials or full stage names of its members: JxW (Jeonghan and Wonwoo), HOSHI X WOOZI, CxM (S.Coups and Mingyu), DxS (DK and Seungkwan), V8 (Vernon and The8), and JxJ (Jeonghan and Joshua). By continuing to introduce new units during the group’s military era, SEVENTEEN have ensured that fans still have group-adjacent projects to follow, alongside solo debuts.

Of course, this rotating formula is easier with larger lineups, similar to NCT, but the concept itself still benefits the groups, the companies, and the fans. In an interview with Tidal in 2023, BSS member DK said, “The purpose of the sub-unit system is to emphasize and showcase individual talent. We often include unit tracks in SEVENTEEN’s albums and EPs, so listening to them is an easy way to discover each unit and individual member’s charm.”

The subunit formula has both thrived and evolved quite a lot since its early days in the 2000s, but even through all the industry’s changes over the years, it's never gone out of style as one of the most efficient ways to keep K-pop groups active, relevant, and ever-intriguing. While fans love their main groups and relish seeing them all together, they also love fresh takes and bold choices that come from pairing individual members and not knowing what to expect.