Kang Ye Seo: From Kep1er to MADEIN - The Untold Story

Kang Ye Seo made headlines in 2024 when she transitioned from the globally recognized girl group Kep1er to becoming a member of MADEIN under 143 Entertainment. Initially debuting with Kep1er on January 3, 2022, after securing 6th place with 770,561 points in the Mnet survival show Girls Planet 999, her journey in the K-pop industry has been nothing short of remarkable.

Throughout her career, Yeseo has demonstrated impressive versatility as both a singer and actress. Before joining Kep1er, she was notably a member of the girl group Busters and the children's group CutieL. However, her chapter with Kep1er came to an end when she decided not to renew her contract, officially concluding her activities with the group after their scheduled Japanese concert on July 15, 2024.

Early Life and First Steps in Entertainment

Born on August 22, 2005, in Incheon, South Korea, Kang Ye Seo comes from a close-knit family consisting of her parents and an older brother. Despite her young age, she has built an impressive resume spanning both acting and singing careers that began at a remarkably early stage in her life.

Birthplace and family background

Kang Ye Seo's formative years were spent in Incheon, where she first displayed her natural talent for performing arts. Throughout her early childhood, her family provided strong support for her budding career in entertainment. During her early career, she attended Eungye Middle School and subsequently enrolled at Lila Art High School, with an expected graduation year of 2024. Furthermore, she has continued her education in the performing arts by enrolling in the theater program at Dongguk University, demonstrating her commitment to developing her craft beyond just practical experience.

Yeseo's debut age and early acting roles

Kang Ye Seo stepped into the entertainment industry at the remarkably young age of 5 when she made her acting debut in 2010. Her first role came in the MBC drama "Golden Fish," where she portrayed the character Moon Seoyeon. That same year, she also appeared in the SBS drama "Smile, Mom" as Shin Yura, establishing herself as a promising child actress.

As her career progressed, she accumulated an impressive list of acting credits. In 2011, she took on roles in "Brain" (KBS2) as Choi Ruby and appeared in two KBS Drama Specials: "Men Cry" as Lim Juhee and "Duet" as Han Joonhwi. The following year proved equally productive with appearances in "The Korean Peninsula" (TV Chosun), "Angel's Choice" (MBC), and "Dream of the Emperor" (MBC), where she portrayed child Princess Yeonhwa.

A significant breakthrough in her acting career came in 2013 with her role in the acclaimed film "Miracle in Cell No. 7" as Choi Ji-yeon. Her character's iconic Sailor Moon backpack helped boost the anime's popularity in Korea. This role particularly resonated with audiences and contributed to her growing recognition as a talented child performer.

Her acting career continued through her adolescence with roles in productions such as "Ancient Beast" (SBS, 2017), "One Step" (2017), "Abyss" (tvN, 2019), and "Diary of a Prosecutor" (JTBC, 2020). By this point, she had accumulated approximately 10 years of experience as a child actress.

Joining CutieL and early music exposure

Alongside her acting career, Kang Ye Seo simultaneously ventured into the music industry. In 2010, the same year as her acting debut, she became an original member of the children's music group CutieL. The group's name cleverly combined the words "cutie" and "angel", reflecting their youthful concept.

CutieL officially debuted on December 17, 2010, under Big Star Entertainment with their first digital single titled "Christmas Carol" (also referred to as "Cutie Carol" in some sources). At the time of her debut with CutieL, Kang Ye Seo was merely 5 years old, making her one of the youngest idol group members in K-pop history. During this period, her profile listed her height as 103cm (3'4″) and weight as 17kg (37lbs), highlighting just how young she was when beginning her entertainment career.

The formation of CutieL had an interesting background—Big Star Entertainment specifically created the children's group by gathering several young actors. Kang Ye Seo remained with CutieL's first generation from 2010 until 2013, after which she departed the group to focus more intensively on her acting career.

Acting Career Before K-pop

Long before stepping into the K-pop spotlight, Kang Ye Seo built an impressive acting portfolio spanning numerous productions across television and film. Throughout her childhood and early teens, she established herself as a versatile child actress, gradually transitioning toward her eventual path as an idol.

Notable dramas and films

After her initial acting debut in 2010, Kang Ye Seo's on-screen presence expanded considerably. In 2011, she took on meaningful roles in "Brain" as Choi Ruby and appeared in two KBS Drama Specials: "Men Cry" and "Duet". The following year proved exceptionally productive as she participated in multiple productions including "The Korean Peninsula," "Angel's Choice," and "Dream of the Emperor".

Her breakthrough moment arrived in 2013 with the critically acclaimed film "Miracle in Cell No. 7," where she portrayed Choi Ji-yeon. This performance garnered significant attention, especially for her character's iconic Sailor Moon backpack, which inadvertently boosted the anime's popularity across Korea. The film itself achieved an impressive 9.1 rating, marking it as one of her most significant contributions to Korean cinema.

Moreover, Kang Ye Seo's filmography continued to grow with roles in:

"Flower of Revenge" (2013) as Yoo Yeji
"Forgive Me" (2014) as child Minji
"One Step" (2017) as child Sihyun
"Ancient Beast" (2017) as Song Haeun
"Abyss" (2019) as both child Jang Heejin and child Oh Sujin
"Diary of a Prosecutor" (2020) as Yang Eunjung

By 2020, she had accumulated an impressive repertoire of almost 20 drama appearances, establishing herself as a recognizable talent in the Korean entertainment industry despite her young age. Her acting contributions spanned various genres and character types, demonstrating remarkable versatility for someone who began her career at just five years old.

Transition from child actress to idol trainee

While balancing her flourishing acting career, Kang Ye Seo began exploring new avenues in the entertainment industry. In contrast to many K-pop idols who train for years before debuting, her transition path was unique due to her pre-existing career in entertainment.

By late January 2019, Kang Ye Seo pivoted significantly in her career trajectory when she joined JTG Entertainment and Marbling E&M's girl group Busters as their newest lead vocalist. This decision came after the departure of previous member Minjung. She officially debuted with Busters on July 31, 2019, with their first extended play "Pinky Promise", although some sources indicate she first appeared in their digital single "Starlight" on July 11, 2019.

Her tenure with Busters was relatively brief, as she left the group on August 6, 2020. According to reports, she departed to continue pursuing acting and other activities, suggesting that she was still exploring different paths within the entertainment industry.

In a surprising development, on April 29, 2021, 143 Entertainment released photos of Kang Ye Seo on their social media accounts, confirming her status as a trainee under their agency. This announcement signaled yet another shift in her career direction. Shortly thereafter, on July 7, 2021, she was confirmed as a contestant on Mnet's reality show "Girls Planet 999", which would ultimately lead to the next significant chapter in her journey.

This series of career shifts demonstrates Kang Ye Seo's willingness to explore multiple facets of the entertainment industry, leveraging her experience as a child actress while pursuing new opportunities in the idol world.

Joining Busters and the Pre-Kep1er Phase

In early 2019, Kang Ye Seo ventured into the idol world by joining an established girl group—a significant career pivot from her acting roots. This period marked an important transitional phase in her journey toward eventually becoming a member of Kep1er.

How she joined Busters

Kang Ye Seo became part of Busters on February 1, 2019, when she was recruited by JTG Entertainment to replace departing member Minjung. At just 14 years old, this transition represented her first official step into the world of K-pop idol groups since her earlier days with the children's group CutieL. The addition of Yeseo was part of Busters' ongoing lineup changes, as the group frequently adjusted its membership throughout its existence.

Prior to her debut with Busters, the group had been formed initially to promote Monstergram's TV series "Idol Rangers Power Busters". By bringing in Yeseo, management likely hoped to capitalize on her existing recognition from her acting career while strengthening the group's vocal lineup, as she joined as their new lead vocalist.

Key performances and releases

Yeseo made her official debut as a Busters member with their digital single "Starlight" released on July 11, 2019. This track served as a pre-release for their upcoming extended play. On July 31, 2019, the group released their first EP titled "Pinky Promise," which marked Yeseo's full-fledged debut with the group.

Throughout her time with Busters, the group underwent several additional member changes. In November 2019, Minji left the group, followed by the addition of new member Jieun in December. By March 2020, two more members joined—Takara and a new Minji—making Busters a six-member group. Interestingly, Yeseo helped Takara learn Korean while Takara assisted Yeseo with Japanese, demonstrating her collaborative spirit within the group.

Reasons for leaving the group

On August 6, 2020, after approximately 18 months with Busters, Marbling Entertainment announced that Yeseo would be leaving the group. The official statement indicated she was departing to "continue acting and other activities", yet behind this standard industry explanation lay more concerning circumstances.

In fact, during her time with Busters, Yeseo experienced a frightening incident with a stalker. In her hometown of Siheung, after concluding a V Live broadcast at around 11 p.m., she was followed and photographed by a sasaeng fan in a dark alleyway. This disturbing encounter reportedly contributed to her decision to leave the group, as she later explained to fans that she "couldn't deal with meeting people who were blindly in love with her".

Additionally, the group's concept raised concerns. Busters consisted primarily of underage members yet promoted with what some sources describe as a "Lolita concept" with potentially sexualized content despite the members' young ages.

A year after leaving Busters, Yeseo pursued her idol dreams by joining 143 Entertainment as a trainee and competing on Mnet's survival show "Girls Planet 999", which would ultimately lead to her next significant career chapter.

Girls Planet 999: The Turning Point

On July 18, 2021, Kang Ye Seo embarked on her journey to stardom as an official contestant on Mnet's survival show Girls Planet 999. Representing 143 Entertainment, this competition would ultimately reshape her career trajectory and propel her toward global recognition.

Initial ranking and team performances

The competition began with Yeseo receiving a K13 ranking in the signal song evaluation, positioning her in the middle of the K-Group contestants. For her first performance, she joined Team Monster Baby alongside Guinn Myah, Kim Chaeyun, and Kim Sein to showcase 4Minute's "Crazy". Her professionalism shone brightly when her mic pack fell off mid-performance—instead of panicking, she discreetly slipped it into her pocket and continued flawlessly.

Throughout the show, Yeseo formed various cells with fellow contestants. Initially, she teamed up with Huang Xingqiao and Sakamoto Mashiro in a cell called "Let's Go Up the Mountain". Her performances consistently impressed both judges and viewers alike. For the Connect Mission, she performed IZ*ONE's "Fiesta" with Team 1 (Team Crown), which secured a victory. Likewise, her rendition of Lee Sunhee's "Fate" with the 6-girl Team "Present" also claimed a win.

As the competition progressed, her rankings fluctuated—at one point reaching as high as K2 in episode 5's individual voting results. By episode 8, she held the K4 position, showing her consistent popularity among viewers.

Final results and fan reception

On October 22, 2021, during the final episode of Girls Planet 999, Yeseo secured 6th place with an impressive 770,561 points, ensuring her debut with the newly formed group named Kep1er.

In her emotional winning speech, she revealed: "At first, when masters chose the rank, my rank went down and down again. So this time around, I didn't think I could be in the Top 9, and that made me suffer." She expressed gratitude to fans (called Planet Guardians), staff members, and her family.

Her motto and standout moments

Throughout the competition, Yeseo characterized herself with the charming motto: "Lovely YE SEO twinkling like a jewel", perfectly capturing her bright personality and stage presence.

Beyond performances, she created memorable moments off-stage too. In an interview after debut, she revealed that contestants would make beaded bracelets and rings to give as presents to one another regardless of national grouping, highlighting the camaraderie amidst competition.

Her final performance on Girls Planet 999 included the Creation Mission song "Utopia" with Team UNICORN. Fellow Kep1er member Choi Yujin later mentioned that although she wasn't part of this performance, she particularly enjoyed Yeseo's "Utopia" stage, noting it displayed her charm well.

Kep1er Era: Rise to Global Fame

After finishing in 6th place on Girls Planet 999, Kang Ye Seo's path to K-pop stardom was officially sealed. Alongside eight other finalists, she became part of a highly anticipated project group that would soon capture global attention.

Debut with Kep1er and 'First Impact'

January 3, 2022 marked a pivotal milestone as Kang Ye Seo officially debuted as a member of Kep1er with the release of their first EP, "First Impact". The group's debut had actually been scheduled for December 2021, yet faced a slight delay due to COVID-19 concerns. Their debut EP featured six tracks total, with "WA DA DA" serving as the title track. The album achieved immediate commercial success, selling approximately 400,000 copies and peaking at number 1 on South Korea's Gaon Album Chart.

The name "Kep1er" carried significant meaning—combining "kep," representing catching dreams, with the number one, symbolizing the nine members coming together as one to be the best. This name certainly proved fitting as the group made their first impression on the K-pop landscape.

Popular songs and performances

"WA DA DA," Kep1er's energetic debut title track, quickly became their signature song. Written by a team including Shannon Bae, Kako, and several others, the song expressed the group's ambitions to achieve their dreams together. Its catchy pre-chorus and chorus showcased their "girl crush" sound, with the line "Kep one going, wa-da-da-da" becoming instantly recognizable.

Beyond their title track, First Impact included five other songs:

Three tracks previously performed on Girls Planet 999: "O.O.O," "Shine," and "Another Dream"

Kang Ye Seo's individual performance of "WA DA DA" gained attention through Studio Choom's UNFILTERED CAM series, where her precise choreography execution and stage presence were highlighted.

Yeseo's role and image in the group

Within Kep1er's dynamic, Kang Ye Seo held the position of vocalist and was notably the group's maknae (youngest member). Her extensive background in entertainment—from child actress to idol—brought valuable experience despite her young age.

Fans frequently praised Yeseo for being "definitely the cutest", with her youthful charm balanced by professional performance skills developed throughout her decade-plus career. Her distinctive appeal earned her dedicated support even as she managed the challenging transition from child actress to globally recognized idol.

Throughout Kep1er's promotional activities, Yeseo continued developing her abilities alongside the other members, contributing significantly to the group's initial impact on the K-pop scene.

Departure from Kep1er and Health Break

After a two-and-a-half-year journey with Kep1er, Kang Ye Seo's chapter with the group came to a close through an official announcement that surprised many fans.

Announcement of contract non-renewal

On May 30, 2023, WAKEONE and SWING Entertainment revealed that only seven of Kep1er's nine members had agreed to extend their contracts with the labels. Kang Ye Seo and Mashiro, both from 143 Entertainment, opted not to renew their contracts and would be concluding their activities with the group.

At that time, the agencies stated: "As a result of extensive discussion and consensus, Mashiro and Yeseo will conclude their activities as Kep1er after the scheduled upcoming concert". Their final group promotions included the release of their first full-length album "Kep1going On" on June 3, followed by a concert in Japan in July.

During the press showcase for their final album as a nine-member group, Yeseo shared her heartfelt sentiments: "I just hope you remember that we will always stay as nine siblings. I tried my best, for [our fanbase] Kep1ian, for everyone". She further emphasized, "I hope everyone remembers that we are always nine sisters", underscoring the deep bond formed among the members despite their upcoming separation.

Health issues and temporary hiatus

Throughout her time with Kep1er, Kang Ye Seo faced several health challenges that temporarily sidelined her from group activities. On July 15, 2022, Kep1er's management announced that she had tested positive for COVID-19. The statement noted she had already completed her second dose of COVID-19 vaccinations. As a result, the group suspended all upcoming schedules to prioritize health and safety.

Afterward, on September 21, 2023, another health concern emerged when WAKEONE and SWING Entertainment announced Yeseo would not be attending the 2023 KPOP NATION X Korea Music Festival in Poland. The announcement explained her health had "suddenly taken a turn for the worse," necessitating rest while the event proceeded with the remaining eight members.

Fan reactions and support

For the most part, fans responded with overwhelming support through both Yeseo's health struggles and her eventual departure from Kep1er. When news broke about her contract non-renewal, many expressed sadness but respected her decision.

Coupled with concern about her well-being, some fans pointed out that at just 19 years old, Yeseo had already been part of multiple groups. After leaving Kep1er, she maintained connection with supporters primarily through private fan chats, keeping a relatively low profile before her next career move.

All things considered, Yeseo's departure marked the end of an era for both the artist and Kep1er's original lineup, setting the stage for her next chapter in the industry.

Re-debut with MADEIN: A New Chapter

Following her departure from Kep1er, a fresh opportunity emerged for the talented performer in mid-2024. In June 2024, it was officially announced that Yeseo would join 143 Entertainment's upcoming girl group after concluding her contract with Kep1er.

Joining 143 Entertainment

The transition unfolded rapidly as 143 Entertainment prepared for a significant brand refresh. On July 15, 2024, all social media accounts belonging to LIMELIGHT were completely rebranded as MADEIN, signaling a new direction for the company's girl group project. Shortly thereafter, on July 16, reports emerged that both Kang Ye Seo and her former Kep1er groupmate Mashiro would be joining this newly rebranded group with plans to debut in September 2024.

The official announcement came on July 29, when 143 Entertainment formally introduced Yeseo as a member of the seven-member lineup alongside Mashiro, MiU, Gaeun, Suhye, Serina, and Nagomi. This confirmation generated considerable excitement among fans who had followed her journey from Kep1er to her next chapter.

MADEIN debut and concept

MADEIN, stylized as MΛDEIN, made their highly anticipated debut on September 3, 2024 with their first EP titled "Rise" (상승). The EP featured four tracks: "UNO" (the title track), "DADARIDA," "DOPAMINE," and "TIMELINE". According to promotional materials, the title track "UNO" was designed to "capture the heartwarming emotions of the present moment and express the excitement of the beginning of a new journey".

Notably, the group name MADEIN carried special meaning—standing for "WE MADEIN U," suggesting the group was created with fans' love as its foundation, particularly given many members' previous experiences in survival shows.

Yeseo's role in the new group

Within MADEIN, Kang Ye Seo took on the center position, a natural fit given her extensive performance background and strong stage presence. At age 19, she became the fourth group she had debuted with throughout her career, demonstrating her remarkable persistence in the industry.

Following their debut, MADEIN quickly established their presence with their first fan concert titled "MADEIN ADVENTURE 2024" held at the Orix Theater in Osaka, Japan on October 5-6, 2024. The group's fanbase received the official name "MABY" (pronounced like "maybe"), a combination of the group's name and the English word "by".

Unfortunately, MADEIN faced challenges almost immediately when member Gaeun left the group in November 2024 due to "personal circumstances," reducing the lineup to six members. Nevertheless, Kang Ye Seo continued her activities with the group as they moved forward with their musical journey.

Fun Facts and Personal Life

Beyond her impressive career achievements, Kang Ye Seo possesses a multifaceted personality and rich personal life that many fans find equally captivating.

MBTI and personality traits

Initially identifying as an ENFJ personality type, Yeseo later updated her MBTI to ENFP, revealing her evolving self-awareness. Surprisingly, despite her confident stage presence, she describes herself as "shy and socially awkward" in school settings. This duality shows in her interactions—Yeseo often appears timid when meeting new people yet becomes incredibly talkative with close friends.

One particularly endearing trait is her tendency to talk extensively, even following her roommate Mashiro to the bathroom to continue conversations. She talks in her sleep, further highlighting her naturally expressive nature. Considering herself "a timid person," she has openly acknowledged struggling to make friends outside her immediate circle.

Hobbies and favorite things

Yeseo's leisure pursuits include drawing, reading webtoons, and watching movies. Her favorite color is light purple, while she considers puppies her favorite animal. Her self-identified charming point? Her "rabbit eyes"—a feature fans indeed find distinctive.

Her palate shows clear preferences—Yeseo enjoys cold bean soup noodles, tomato spicy seafood noodles, and pork backbone stew. Conversely, she absolutely dislikes eggplant, mussels, and jellyfish. Among her miscellaneous favorites are mint chocolate, notebooks, books, spring weather, and fried chicken. Her stress reliever of choice remains simply sleeping.

Friendships and fan interactions

Perhaps most notable is Yeseo's close friendship with former Kep1er and current MADEIN groupmate Mashiro. When living together in the Kep1er dorm, they shared a room and frequently spent their days off together. Mashiro has played a crucial role in helping the naturally shy Yeseo make new friends.

Regarding fan interactions, Yeseo has expressed a strong desire to hold fan signs. She considers fans among her "favorite things" alongside family members and drawing. Her enthusiastic reactions during performances have made her a fan favorite, with many praising her expressive responses as "priceless". These genuine interactions undoubtedly contribute to her enduring appeal across multiple debut groups.

FAQS

Curious fans frequently ask questions about Kang Ye Seo's unique traits and talents. How did she earn her nickname in Kep1er? Fans might be surprised to learn that Yeseo was known as the "Human Radio/Jukebox" because she could sing along to entire songs while the group listened to the radio or Spotify. What makes her role in Kep1er unique? Expressly noted for having the lowest singing voice in the group, she also earned the nickname "Breakfast Chef" and "Kirby" for cleaning up leftover food after members finished eating.

Does Yeseo speak other languages? Though she can partly write in Japanese (thanks to Mashiro's influence), she isn't fluent in speaking or reading it. Interestingly, she communicates with Hikaru using signs and body language despite language barriers.

What are her personal preferences? Besides being a devoted Samsung fan who received a Z Fold 2 as a 2021 birthday gift (later upgrading to Z Fold 3), she enjoys pasta and tteokbokki. From time to time, she indulges her childhood love of Boys Over Flowers by wearing red checkered skirts and berets.

Any achievements outside K-pop? In 2023, Yeseo took her CSAT test at her mother's alma mater and obtained her driver's license.