Who is Moonbyul? Inside MAMAMOO's Rapper Journey From Trainee to Solo Star

Moonbyul has songwriting credits on over 100 songs, showcasing her immense talent as one of K-pop's most prolific artist-composers. Originally auditioning as a vocalist, she later switched to become a rapper, demonstrating the versatility that would become her trademark as a member of the powerhouse girl group MAMAMOO.

Born on December 22, 1992, in Bucheon, South Korea, Moonbyul (문별) has established herself as a multifaceted performer in the K-pop industry. She debuted with MAMAMOO on June 18, 2014, before eventually launching her solo career with the digital single "Selfish" on May 23, 2018. Her musical journey has been remarkable, with her first studio album "Starlit of Muse" selling over 100,000 copies in its first week alone — a testament to her growing popularity as a solo artist.

Early Life and Musical Aspirations

Moon Byul-yi spent her early years in Bucheon, Gyeonggi-do, South Korea, where she was born on December 22, 1992. As the eldest among three sisters, Moonbyul's childhood aspirations were quite different from her eventual career path. Initially, she dreamed of becoming a teacher. During her middle school years, her ambitions shifted toward becoming a police officer. However, a pivotal moment in her adolescence would dramatically alter her career trajectory.

Childhood in Bucheon and family background

Growing up in Bucheon, Moonbyul enjoyed a supportive family environment that would later prove crucial to her artistic journey. Despite her early career aspirations being unrelated to entertainment, her parents ultimately supported her dream of becoming a singer. This family support system provided the foundation for her to pursue what would become a successful career in music.

Inspiration from TVXQ and Girls' Generation

Moonbyul's passion for music ignited during her third year of middle school after witnessing TVXQ's powerful performance of "Rising Sun". This performance marked the beginning of her interest in singing. Subsequently, she received positive feedback during a school performance, which further convinced her to pursue singing as a career.

Furthermore, Girls' Generation played a monumental role in shaping Moonbyul's aspirations. She particularly admired the group's leader, Taeyeon, who became her primary inspiration. In fact, watching Girls' Generation's "Into The New World" performance served as the final catalyst that compelled her to follow in Taeyeon's footsteps.

Interestingly, Moonbyul initially had no plans to become an idol, having originally intended to become a teacher. Nevertheless, her growing admiration for K-pop artists changed her course. She was especially surprised to discover that Wonder Girls' members Sunmi and Sohee were the same age as her, which made her dream seem more attainable.

Determined to follow her newfound passion, Moonbyul:

Attended the same academy as Taeyeon
Used Girls' Generation songs for her practice sessions
Worked diligently to develop her skills and received applause in competitions

Her dream came full circle when she met Taeyeon on the show "Amazing Saturday," a moment that confirmed her successful journey from fan to fellow artist.

Education at Paekche Institute of the Arts

Moonbyul's formal education supported her musical ambitions. After graduating from Wonmi High School, she took a significant step toward her dreams by attending SM Academy during her first year of high school, with hopes of eventually signing with SM Entertainment. Although she never became a trainee at SM Entertainment, this experience strengthened her resolve.

In 2011, Moonbyul reached another milestone when she was accepted into the Paekche Institute of the Arts, where she majored in media music and vocals. This educational background provided her with the technical foundation necessary for her future career. During this same period, after auditioning for multiple agencies, she was accepted into RBW Entertainment (formerly WA Entertainment), setting the stage for her eventual debut with MAMAMOO.

Throughout her three-year training period, Moonbyul refined her skills, ultimately transforming from an aspiring vocalist to one of K-pop's most distinctive rappers.

From Trainee to MAMAMOO Debut

After numerous auditions and facing several trainee contracts and scams, Moon Byul-yi's persistence finally paid off. Her journey as a K-pop idol began to take concrete shape as she entered the training system that would ultimately lead to her debut as a member of one of K-pop's most distinctive groups.

Joining RBW in 2011

Moonbyul's path to stardom solidified when she was accepted into RBW Entertainment (formerly known as WA Entertainment) in 2011. At this stage, the young aspiring artist had already attended SM Academy with hopes of signing with SM Entertainment, yet fate had different plans. Throughout this period, she balanced her training with her studies at the Paekche Institute of the Arts, where she majored in media music and vocals.

The trainee life was far from easy. Moonbyul faced numerous challenges as she worked to refine her skills under RBW's guidance. While many K-pop trainees undergo years of preparation before debuting, her three-year training period was marked by rigorous practice, monthly evaluations, and constant growth.

Switching from vocalist to rapper

Curiously, Moonbyul's original path at RBW looked quite different from what fans would eventually come to know. She initially passed her audition and trained as a vocalist, showcasing the singing abilities she had developed since being inspired by TVXQ and Girls' Generation.

Nonetheless, a significant turning point arrived when RBW's producer suggested she switch to becoming a rapper. The company's vision for their new girl group required a rapper to balance the team's sound, and Moonbyul was selected for this role. According to some sources, the directive was quite straightforward—"become a rapper or don't debut"—giving her little choice but to embrace this new direction.

Though unfamiliar with rap at first, Moonbyul accepted the challenge just six months prior to debut. This dramatic shift would prove to be fortuitous, as she discovered a hidden talent that would become central to her identity as a performer. Solar, who would become MAMAMOO's leader, helped Moonbyul along the way as she wrote all her own raps from debut onward.

Debut with MAMAMOO in 2014

Prior to MAMAMOO's official introduction to the world, the group participated in several strategic collaborations that helped establish their presence:

January 8, 2014: Released "Don't Be Happy" with Bumkey
February 11, 2014: Collaborated with K.Will on "Peppermint Chocolate" featuring Wheesung
May 30, 2014: Released "HeeHeeHaHeHo" with rap duo Geeks

At last, on June 18, 2014, Moonbyul officially debuted as MAMAMOO's main rapper and performer with the release of their first EP titled Hello and its lead single "Mr. Ambiguous". The music video featured cameo appearances from notable K-pop figures including CNBLUE's Jonghyun, Baek Ji-young, Wheesung, Jung Joon-young, Bumkey, K.Will, and Rhymer of Brand New Music.

The group's name "MAMAMOO" was chosen to symbolize a baby babbling for the first time, reflecting their aim to create music that would feel familiar to everyone around the world. Their first live performance took place on the June 19 episode of M Countdown, marking the beginning of what critics would later call one of the best K-pop debuts of 2014.

Even after joining MAMAMOO, Moonbyul initially found it challenging to find her footing within the group. Yet, over time, she grew confidently into her role as the group's rapper, proving that sometimes unexpected paths lead to the most rewarding destinations.

Establishing Her Role in MAMAMOO

As MAMAMOO gained recognition in the K-pop industry, Moonbyul carved out her unique identity within the group, transforming from a reluctant rapper to a cornerstone of their distinctive sound. What began as an unexpected career pivot would ultimately showcase her multifaceted talents on the K-pop stage.

Performance and rap contributions

Moonbyul's journey as MAMAMOO's main rapper began with uncertainty. Despite originally passing her audition as a vocalist and training in that capacity, she was asked to switch roles just six months before debut. What started as an unfamiliar challenge soon became her signature strength as she embraced the position of main rapper and performer when MAMAMOO officially debuted on June 18, 2014.

Beyond rapping, Moonbyul specialized in freestyle dance and hip-hop, regularly presenting self-choreographed routines during monthly evaluations. This dual focus established her as one of the members specifically in charge of performance aspects within the group.

Over time, Moonbyul grew increasingly confident in her role. As stated in a recent interview, "My image as the MAMAMOO rapper and the girl crush persona was so dominant that I couldn't escape them no matter how well I sang vocally". This statement reflects both the success of her transition to rapper and her desire to continue expanding her artistic horizons.

Songwriting and choreography

Moonbyul's creative contributions to MAMAMOO extend far beyond her performance abilities. As of February 2025, the Korea Music Copyright Association has an impressive 125 songs listed under her name, demonstrating her prolific songwriting capabilities. She has co-written many of the group's lead singles, crafting the entirety of her own rap verses since the release of their second EP Piano Man in November 2014.

Her choreographic talents also proved valuable to the group. Notably, Moonbyul contributed to creating the dance routines for MAMAMOO's debut track "Mr. Ambiguous", adding her distinctive style to the group's visual presentation. During MAMAMOO's appearances on Immortal Songs 2, she displayed additional versatility by writing rap parts for songs that originally had none.

Notable group performances and viral moments

MAMAMOO quickly gained recognition for their exceptional live performances, particularly with live bands. These appearances demanded heightened musicality and showmanship, as the singers needed to perfectly deliver vocals while matching the energy and dynamics of instrumentalists.

A defining moment came in November 2016 when MAMAMOO performed at the 37th annual Blue Dragon Film Awards, one of South Korea's most prestigious entertainment events. During their rendition of "Decalcomanie," Moonbyul delivered a memorable line directed at actor Jung Woo-sung: "Jung Woo-sung, if I drink this in one shot, will you go out with me?". This improvised moment captivated audiences, went viral on social media with 1.5 million views within a day, and contributed to the song climbing real-time music charts.

MAMAMOO's performances with live bands consistently showcased their musical prowess. Their adaptability allowed them to transform songs like:

"Yes I Am" on JYP's Party People, featuring mind-blowing vocal intros and adlibs
"Mr. Ambiguous" on Mdromeda It's LIVE, demonstrating their growth from rookie to veteran performers
"gogobebe" at the 2019 M2 x Genie Music Awards, where they transformed their electro-pop dance track into an entrancing rock concept

Through these performances and viral moments, Moonbyul solidified her position as an integral part of one of K-pop's most vocally-centered and performance-driven groups.

Moonbyul’s Solo Debut and Early Releases

While continuing to thrive as MAMAMOO's main rapper, Moonbyul began crafting her individual artistic identity in 2018, marking a significant evolution in her career trajectory beyond group activities.

Release of 'Selfish' with Seulgi

Moonbyul's solo journey officially commenced on May 23, 2018, with the digital single "Selfish" featuring Red Velvet's Seulgi. The track quickly made its mark, landing at #4 on Billboard's World Digital Song Sales chart and reaching #26 on the Gaon Digital Chart. Throughout the promotional period for "Selfish," Moonbyul established her distinctive solo persona - balancing her trademark powerful rap style with a more melodic approach.

Following this successful debut, Moonbyul continued building her solo presence through participation in OSTs and special projects. Her performance on "Studio Music Hall" in December 2018 solidified her growing reputation as an independent artist capable of commanding the stage alone.

First EP: Dark Side of the Moon

On February 14, 2020, Moonbyul reached a major milestone with the release of her first mini-album (EP) titled Dark Side of the Moon. The six-track project featured the lead single "Eclipse," alongside fan favorites like "ILJIDO" and "Weird Day" featuring Punch.

The EP showcased Moonbyul's artistic range, exploring darker themes and more experimental sounds than her previous work with MAMAMOO. This creative direction paid off commercially as well - Dark Side of the Moon debuted at #8 on the Gaon Album Chart and sold 25,573 copies in its first week, an impressive figure for a female soloist at that time.

Critically, the EP garnered positive reception for its cohesive storytelling approach and Moonbyul's evolved artistry. "Eclipse" particularly highlighted her growth, blending hip-hop elements with her increasingly confident vocal delivery.

Repackage album: 門OON

Just two months after her EP release, Moonbyul presented fans with a repackaged version titled 門OON on May 29, 2020. This expanded edition included all tracks from the original EP plus two new songs: "Absence" and the lead single "Satellite."

"Satellite" offered a brighter counterpoint to "Eclipse," demonstrating Moonbyul's versatility across different moods and concepts. The music video for the track emphasized her charismatic performance style, incorporating both her sharp dance skills and emotional delivery.

The repackage strategy proved effective, extending the album's commercial lifespan and providing fans additional content during a period when in-person events were limited due to global health concerns. Together, these releases established Moonbyul not merely as a talented group member but as a formidable solo artist with her own distinctive musical identity.

Musical Growth and Conceptual Albums

Following her early solo releases, Moonbyul embarked on a creative journey of musical evolution that showcased her growing confidence as a solo artist through increasingly ambitious concept-driven projects.

6equence and storytelling through music

In January 2022, Moonbyul unveiled her third EP, "6equence," a project in which she participated "from A to Z in the EP-making process". The six-track album was meticulously crafted with a "cinematic flow," telling a cohesive story across its runtime. Rather than random singles, the EP intentionally progressed through the various stages of romantic relationships, from first encounters to breakups.

"I think many listeners will find it relatable, as its main theme is love," Moonbyul explained about the album. Her lead single "Lunatic," a house track focusing on ennui, surprised fans with its upbeat sound despite the melancholic teasers. This artistic misdirection demonstrated her growing mastery of nuanced storytelling.

Another standout track, "Ddu ddu ddu," explored lingering affection after relationships end—a theme Moonbyul admitted resonated with her own past experiences. Throughout the EP, she maintained her commitment to creating gender-neutral music that could "challenge the binary view of gender", further establishing her unique voice in K-pop.

C.I.T.T and genre experimentation

Merely three months after "6equence," Moonbyul shifted musical directions yet again with "C.I.T.T (Cheese in the Trap)" in April 2022. This release marked her most significant genre experiment to date, embracing pop-rock sounds that energized listeners.

Critics noted that this stylistic pivot suited her personality perfectly, allowing her "to let loose". The album's concept cleverly incorporated themes of mice, cheese, and mousetraps across its three versions: "Jerry," "Cheese," and "Trap".

"C.I.T.T" proved commercially successful alongside its artistic merits, surpassing 101,000 copies in its first week on the Hanteo Chart—an achievement that earned the album a Hanteo Chart Initial Chodong Bronze Certificate. This recognition validated Moonbyul's willingness to explore new musical territories beyond her established comfort zone.

Starlit of Muse and first full album

The pinnacle of Moonbyul's solo discography thus far arrived on February 20, 2024, with the release of "Starlit of Muse"—her first full-length studio album. The project featured two contrasting title tracks, "Think About" and "TOUCHIN&MOVIN," highlighting her commitment to diverse musical styles.

Even the album's title contained meaningful wordplay, referencing Moonbyul herself as a muse alongside her name's meaning—"Byul" (별) translates to "star" in Korean. This clever self-reference illustrated her growing artistic confidence.

Commercially, "Starlit of Muse" became Moonbyul's most successful release, selling an impressive 101,720 copies in its first week. This achievement underscored her evolution from group member to established solo artist with a dedicated fanbase.

Correspondingly, the album's success led to the announcement of her first world tour, "MUSEUM: an epic of starlit," on February 29, 2024—a landmark milestone in her solo career that positioned her for even greater global recognition.

Beyond Music: Hosting and Variety Shows

Not limiting herself to musical pursuits, Moonbyul expanded her presence in the Korean entertainment industry through various hosting roles and variety show appearances that showcased her versatility beyond singing and rapping.

Studio Moon Night and Avengirls

In July 2020, Moonbyul ventured into radio hosting when she was appointed as the host for the weekly radio program Avengirls on Naver NOW. The show featured a different girl group member each night, with Moonbyul taking over the Tuesday time slot. After garnering high broadcast ratings, she launched her own flagship talk show, Studio Moon Night, on February 15, 2021.

This milestone made Moonbyul the first MAMAMOO member to venture into hosting and have a program named after her. Moreover, she composed and wrote the theme song for the show herself, demonstrating her multifaceted talents. The show was renewed for a second season in March 2022 after marking its first anniversary. In recognition of her hosting skills, Moonbyul received the 2022 Korea Brand Customer Loyalty Index award in the live broadcasting category.

Kick a Goal and The Second World

Alongside her hosting duties, Moonbyul joined the cast of SBS entertainment program Kick a Goal in October 2021. As part of "FC Top Girl," a team formed of former girl group members, Moonbyul initially struggled with scoring goals despite her defensive skills and assists. Her perseverance paid off when she scored her first goal on August 24, 2022, helping her team advance to the Super League—an episode that recorded impressive viewership ratings of 9.6%.

From August to November 2022, Moonbyul participated in and ultimately won JTBC's survival program The Second World, a competition where K-pop girl group rappers showcased their vocal abilities. Throughout the show, she consistently secured top scores in multiple rounds. Her stellar performance led to the phrase "어우문" (an acronym meaning "Moonbyul is going to win anyway") gaining popularity among viewers.

YouTube and fan engagement

On December 20, 2021, Moonbyul launched her YouTube channel, "moonbyul2da," creating yet another platform to connect with her audience. Her genuine relationship with fans was evident when, after receiving criticism from judges on The Second World for being "too greedy" with her vocal performance, she reassured fans through a fan cafe post: "If I don't have moomoos in my world...I'll be in big trouble, I don't even want to think about it. I will do better!!!!".

Throughout her various media activities, Moonbyul consistently demonstrated an ability to excel beyond her initial role as MAMAMOO's rapper, establishing herself as a multi-talented entertainer with significant appeal across different entertainment formats.

Achievements, Awards, and Recognition

Moonbyul's talents and hard work have earned her impressive recognition throughout her career, cementing her status as both a respected group member and acclaimed solo artist.

Billboard and Gaon chart success

Throughout her solo career, Moonbyul has consistently achieved remarkable chart performance. Her mini-album "Dark Side of the Moon" sold 66,000 copies in its first week of release alone, placing high on the Gaon Chart. The album's lead single "Eclipse" peaked at number fourteen on Billboard World Digital Song Sales chart. More recently, her 2025 mini album "laundri" topped iTunes "Top Album" charts in Hong Kong, Singapore, Taiwan, and Malaysia. This release achieved the impressive feat of entering the worldwide iTunes album chart at 13th position. Equally impressive, the title track "Goodbyes and Sad Eyes" debuted at 20th on the Melon HOT100 and 6th on Genie charts, showcasing her widespread popularity across platforms.

Brand Customer Loyalty Award

In May 2022, Moonbyul received prestigious recognition at the Korea Brand Customer Loyalty Awards for her work as a host in the live broadcasting category. She won the Best DJ – Live Streaming Show award for her program "Studio Moon Night". The Brand Customer Loyalty Awards, held annually by the Korean Consumers Council, recognizes brands and personalities with the most influence on popular culture and society. This acknowledgment demonstrates her impact beyond music, as the winners are determined through consumer research in association with U.S. consulting firm Brand Keys. Alongside Moonbyul, other notable winners included Seventeen, 2PM's Junho, and IU.

Winning The Second World

Undoubtedly one of Moonbyul's most significant achievements came in November 2022, when she won JTBC's survival program "The Second World". This competition featured eight female idol rappers showcasing their vocal abilities. Her consistent excellence throughout the show led to the phrase "어우문" (meaning "Moonbyul is going to win anyway") gaining popularity among viewers. In the final round, she performed the song "Rest", scoring an impressive 4,157 points to secure first place. As the winner, she received the privilege of performing a special stage at the 37th Golden Disc Awards and releasing an OST for a JTBC drama.

Discography and Collaborations Overview

Throughout her solo career, Moonbyul has steadily built an impressive catalog of music spanning various formats while demonstrating her versatility as an artist.

Studio albums and EPs

Moonbyul's discography includes one studio album, Starlit of Muse, released on February 20, 2024, along with its repackage Starlit of Twinkle released on August 21, 2024. This first full-length album featured 12 tracks, including collaborations with artists like Hanhae and Onewe.

Prior to her full album, Moonbyul released several EPs that showcased her artistic evolution. Her first mini-album, Dark Side of the Moon, arrived on February 14, 2020, peaking at #2 on Korean charts. This was followed by its repackage 門OON on May 29, 2020. Her second EP 6equence was released on January 19, 2022, alongside single albums C.I.T.T (Cheese in the Trap) (April 2022) and The Present (December 2022). In total, Moonbyul has released "1 studio album, 1 repackage studio album, 3 mini albums, 1 repackage album, and 3 single albums".

Notable collaborations and features

Moonbyul's collaborative spirit has resulted in numerous musical partnerships, most notably:

"Selfish" featuring Red Velvet's Seulgi (2018), which became her solo debut single
"Nothing" with U Sung-eun (2021)
"The Lady" with Bumkey (2021)
"Promise U" with Solar for VIBE's "REVIBE" project (2021)
"Maybe Love" with David Yong (2022)

OSTs and special singles

Outside her regular albums, Moonbyul has contributed to several soundtracks and special releases. She collaborated with Gaho on "Half of Half" for the webtoon "Hanyang Diaries" and released "Love Blooms" for the JTBC drama "Strong Girl Nam-soon" - notably her "first truly solo-sung OST".

Alongside Solar, she recorded "Like Yesterday" for JTBC's "Two Yoo Project Sugar Man" and "Bada Boom" for "Street Dance Girls Fighter". For her birthday on December 22, she released the special single album The Present, which included previously released birthday songs "A miracle 3days ago" and "CHEMISTRY" alongside a new track "PRESENT".