Yoon STAYC Profile: Surprising Facts You Never Knew (2025 Update)

Yoon STAYC stands tall at 172.6 cm (5'8"), making her the tallest member in the popular South Korean girl group that debuted on November 12, 2020, with their first single album "Star To A Young Culture." Revealed as the sixth and final member on October 15, 2020, Shim Ja-yoon (her full name) trained for just 2 years and 7 months before joining the group, yet has established herself as the second-ranking vocalist.

Beyond her impressive vocal abilities, Yoon's ENFP personality makes her the energetic "life of STAYC," bringing enthusiasm to the group dynamics. Interestingly, she holds a Microsoft Excel certification, demonstrating talents outside the music industry. Born on April 14, 2004, she represents the color green and the element metal within the group. Additionally, her personal motto—"If you can't walk today, you have to run tomorrow"—reflects the determination that has helped her succeed despite her relatively short training period.

Early Life and Background

Born in the vibrant city of Gwanju, Jeolla-do, South Korea, Shim Ja-yoon (better known as Yoon STAYC) grew up in a supportive family environment that would eventually nurture her artistic talents. As the youngest of her parents' two daughters, Yoon developed a close relationship with her older sister during her formative years. Her father, who works as a professional soldier, likely instilled discipline and dedication in her from an early age.

Birthplace and family

Yoon's South Korean heritage plays a significant role in her identity. While many STAYC members come from different regions across South Korea, Yoon represents the southwestern region of Jeolla-do. Moreover, her upbringing in Gwanju provided her with a distinct cultural background compared to other members who hail from Seoul, Busan, Pohang, and Daejeon.

At age 15, Yoon made a life-changing decision to relocate from her hometown to Seoul, doing so halfway through her middle school years. This bold move demonstrated her commitment to pursuing her dreams, nevertheless, it must have been challenging for someone so young to leave her family behind and adapt to life in Korea's bustling capital.

Education and childhood interests

During her educational journey, Yoon attended Dosan Elementary School and later graduated from Gajaewool High School. Throughout her school years, she maintained diverse interests that extended far beyond music.

As a child, Yoon was remarkably ambitious and imaginative. She dreamed of pursuing several different career paths, specifically:

Becoming a professional singer
Training as a ballerina
Working as a scientist

These varied aspirations reflect her multifaceted personality and intellect. Furthermore, Yoon developed some unexpected skills and hobbies that set her apart from typical K-pop idols. Most notably, she obtained a Microsoft Excel certification and developed an interest in woodworking—both unusual talents that highlight her practical nature alongside her artistic abilities.

How she got into music

Initially, Yoon's dream of becoming a singer was merely a thought she kept tucked away "in a corner of her heart". However, everything changed when she observed a friend persistently persuading her parents for a month to allow attendance at a vocal and dance academy. This encounter reignited Yoon's buried passion for music.

With newfound determination, she immediately approached her mother about attending the academy. Fortunately, she received quick permission to begin training. Yoon dedicated herself to practicing at the academy until she successfully secured a position as a trainee.

Unlike some STAYC members who trained at multiple agencies, Yoon began her trainee journey directly with High Up Entertainment in March 2019. Prior to this professional training, she honed her skills at Joy Dance Plug In Academy in Gwangju, establishing a foundation for her future career.

Throughout her training period, Yoon embodied her personal motto: "If you can't walk today, you have to run tomorrow". This philosophy undoubtedly helped her overcome the challenges of preparing for debut while simultaneously adjusting to life in a new city at such a young age.

Yoon’s Journey to STAYC

Following her early music training at Joy Dance Plug In Academy in Gwangju, Yoon's path to K-pop stardom began taking a more definitive shape. Her journey from aspiring vocalist to becoming a crucial member of STAYC demonstrates both determination and natural talent that would soon capture fans' attention worldwide.

Training period and agency entry

Yoon officially began her professional training journey when she joined High Up Entertainment in March 2019. As one of the newer trainees in the company's roster, she had significantly less training time than some of her future groupmates. In fact, her total training period lasted just 2 years and 7 months before debut—impressively short by industry standards.

The company, founded by legendary producer duo Black Eyed Pilseung, recognized Yoon's potential almost immediately. Although she joined without extensive prior experience, her natural vocal abilities and striking visuals made her a promising candidate for their upcoming girl group project.

Throughout her training, Yoon focused intensely on improving her dance skills and vocal techniques. Her background in dance helped her adapt quickly to the demanding choreography requirements, although she had to work diligently to reach the company's high standards in all performance aspects.

Debut timeline and reveal

The buildup to STAYC's debut followed a carefully orchestrated timeline. High Up Entertainment began introducing the members one by one in October 2020, creating anticipation among K-pop fans. Interestingly, Yoon was the last member to be officially revealed to the public on October 15, 2020—just one month before the group's official debut.

As the sixth and final member to be introduced, her reveal completed the STAYC lineup and generated significant buzz. The company strategically showcased her unique visual appeal and vocal capabilities through teaser photos and videos that highlighted her distinctive features.

STAYC officially debuted on November 12, 2020, with their first single album "Star To A Young Culture" featuring the title track "So Bad." This marked the beginning of Yoon's professional career as an idol, transforming her from trainee to official K-pop artist. The debut was particularly noteworthy as STAYC became the first girl group produced by Black Eyed Pilseung.

Why she almost debuted as 'Kiki'

One of the most fascinating behind-the-scenes aspects of Yoon's debut journey involves her stage name considerations. Indeed, she nearly entered the K-pop scene under an entirely different identity. During pre-debut preparations, the management team seriously considered giving her the stage name "Kiki" instead of using her birth name.

This potential alternative name reflects the common industry practice of assigning catchy, memorable stage names to idols. "Kiki" was likely chosen for its bright, youthful energy that matched her personality. Ultimately, after considerable deliberation, the decision was made to have her promote using "Yoon"—a shortened version of her birth name Ja-yoon.

The choice proved successful, as "Yoon" has become instantly recognizable to fans and fits well with STAYC's overall branding. The name maintains her Korean identity while being accessible to international audiences—an important consideration for a group with global aspirations.

Since joining STAYC, Yoon has consistently demonstrated that the company made the right decision in selecting her as the final piece of the group, regardless of what name she performs under. Her journey from trainee to debut showcases the rapid development path that some exceptionally talented idols can experience in the competitive K-pop industry.

Her Role in STAYC

Within STAYC, Yoon has carved out a distinctive position that goes beyond her impressive 172.6 cm height. As a vital component of the group's success, her contributions span vocals, dance, and the essential yet often overlooked role of maintaining team morale.

Lead vocalist responsibilities

As STAYC's lead vocalist, Yoon shoulders significant responsibilities in the group's musical arrangements. Her distinctive vocal color adds depth to STAYC's signature "Teen Fresh" sound, complementing main vocalist Sieun who typically handles the highest notes. Together with other members, Yoon helps create the balanced vocal harmony that has become a hallmark of STAYC's music.

In the studio and during live performances, Yoon demonstrates remarkable versatility. She seamlessly transitions between supporting vocals and taking center stage for key lines. This adaptability makes her an invaluable asset to the group's musical identity, allowing STAYC to maintain their distinctive sound across various musical concepts.

Beyond technical ability, Yoon brings emotional depth to her performances. Her expressive delivery helps convey the messages behind songs like "Beautiful Monster," which she has named as her personal favorite among STAYC's title tracks. "All of us loved this song. When we listened to it for the first time we were like, 'this is going to be huge,'" she shared regarding the track.

Notable performances and high notes

Yoon's vocal talents have shined across multiple STAYC performances. At the 31st Seoul Music Awards, STAYC (Sumin, Sieun, ISA, Seeun, Yoon, J) won the Best Performance Award, showcasing their collective stage presence. The group delivered a memorable mash-up stage of "SO BAD" and "ASAP" with a fresh arrangement that highlighted each member's strengths.

Her candid insights about performances reveal her thoughtful approach to music. When discussing STAYC's single "Teddy Bear," Yoon admitted the group initially felt unsure about the song. "We weren't that confident, and we weren't sure about it," she explained, detailing how they requested a meeting with their producer to express concerns. This professional approach demonstrates her investment in maintaining STAYC's musical quality.

For their "Teenfresh" record, Yoon expressed a personal preference for the B-side "Not Like You" over the title track "Bubble," appreciating its strong lyrical message: "Its lyrics convey a strong message... like, 'I'm different, but you are just wrong', whatever you say, I'll go my way".

Dance skills and center moments

Though not officially designated as the main dancer, Yoon's height and natural movement quality make her stand out during choreographies. Her dance performances consistently draw attention, especially in stages like their Houston KCON appearance where the group collectively demonstrated their growth as performers.

Yoon has also expanded her performance credentials beyond STAYC activities. She has served as:

Special MC on SBS's "Inkigayo"
Special mate on KBS2's "MA1"
Mentor on "Starlight Boys," where she shares her expertise as a vocalist and performer

As a mentor, Yoon brings "a friendly and approachable energy to the show", consistent with her reputation within STAYC. Known as "the most energetic member of STAYC", her enthusiastic presence creates a positive atmosphere during performances and behind-the-scenes moments alike.

This combination of vocal prowess, dance skills, and infectious energy has established Yoon as a crucial element in STAYC's continued rise in the competitive K-pop landscape. Her contributions have helped solidify the group's reputation as a "leading idol group of the 4th generation" through hit songs like "ASAP" and "STEREOTYPE."

Yoon’s Personality and MBTI

Beyond her impressive vocal abilities, Yoon brings a distinctive personality to STAYC that profoundly shapes the group's dynamics. Her energetic presence and approachable nature have made her a fan favorite since debut, earning her the unofficial title of "mood maker" among both fans and fellow members.

ENFP/ENTP traits

Yoon's personality type falls between ENFP (Extraverted, Intuitive, Feeling, Perceiving) and ENTP (Extraverted, Intuitive, Thinking, Perceiving), sometimes shifting between these closely related types. As an ENxP personality, she exhibits several defining traits:

Outgoing and sociable - Yoon thrives in social settings and energizes those around her
Creative thinking - She approaches problems with innovative solutions
Adaptability - Her perceiving trait allows her to remain flexible in changing situations
Enthusiasm - She brings passionate energy to both performances and casual interactions

The "Champion" nickname often associated with ENFPs perfectly encapsulates Yoon's approach to life and relationships. She naturally motivates others through her boundless optimism and genuine interest in their well-being. This personality type aligns perfectly with her role in maintaining group harmony alongside her performing responsibilities.

Mood maker of the group

Among STAYC members, Yoon has established herself as the quintessential "energy booster." According to group dynamics, she consistently maintains high spirits even during challenging schedules or demanding practice sessions. Her bright disposition serves as a counterbalance to more reserved members, creating a harmonious team atmosphere.

Accordingly, Yoon's natural humor manifests in unexpected moments, often breaking tension with spontaneous comments or playful actions. This quality proves particularly valuable during lengthy promotional periods when fatigue might otherwise impact group morale. Her ability to find joy in small moments helps STAYC maintain their fresh, vibrant image both on and off camera.

Furthermore, behind-the-scenes content frequently captures Yoon dancing unexpectedly or initiating impromptu games with other members, showcasing how her personality creates a positive environment. This spontaneity extends to her interactions with fans, where her authentic reactions and expressive nature make her relatable despite her idol status.

How members describe her

Fellow STAYC members consistently characterize Yoon using terms that highlight her energetic presence. Seeun has described her as "the human vitamin" of the group, referring to how Yoon instantly brightens the atmosphere whenever she enters a room. Sumin has noted that "Yoon never seems to run out of energy," emphasizing her consistent positive influence.

ISA once remarked that Yoon possesses "the unique ability to make everyone feel comfortable," pointing to her natural talent for connecting with people regardless of personality differences. This quality makes her particularly effective during group interviews and variety show appearances, where her engaging personality helps showcase STAYC's charm.

Generally, the members agree that Yoon embodies the perfect balance between professionalism and playfulness. While dedicated to perfecting performances, she simultaneously ensures the group environment remains light-hearted and supportive. This combination of work ethic and positive energy makes her an essential component of STAYC's continued success and group chemistry.

Visuals and Style Evolution

Standing out visually among STAYC members, Yoon captivates fans with her distinctive features and evolving style choices that have become part of her signature appeal. Her unique look has made her instantly recognizable even among the competitive landscape of K-pop idols.

Yoon STAYC height and body proportions

At 172.6 cm (5'8"), Yoon holds the distinction of being the tallest member in STAYC. This impressive height, combined with her slender frame, creates striking proportions that fans often comment on. Her tall stature contrasts with the typically more petite average heights in many K-pop girl groups, making her stand out in group formations and choreography.

Alongside her height, Yoon possesses distinctive facial features that contribute to her memorable appearance. These include dark double eyelids, remarkably large eyes, and a high, sharply defined nose. These characteristics create what many describe as an "exotic atmosphere" that distinguishes her from other idols with more traditionally cute appearances.

Signature full bangs and hair colors

Perhaps most iconic in Yoon's visual identity is her signature full bangs hairstyle. Remarkably, she has maintained this look consistently since her debut, making her the only STAYC member to feature bangs as her primary hairstyle. Based on pre-debut photos, she appears to have adopted this style as far back as her middle school years.

Recently, fans have glimpsed rare moments when Yoon appears without her trademark bangs. During a university festival appearance, she wore her hair differently, revealing her forehead completely. This style transformation garnered significant attention, with netizens commenting that she "looks so pretty" and has "a softer vibe without bangs".

Throughout STAYC's promotions, Yoon has experimented with various hair colors while maintaining her signature bangs. For their "RUN2U" recording, she sported light brown hair with parted bangs that revealed a glimpse of her forehead.

Nicknames like 'Barbie Doll' and 'Human Sims'

Yoon's distinctive appearance has earned her several affectionate nicknames among fans:

Barbie Doll: References her doll-like features and perfect proportions
Human Sims: A clever pun on her name (Shim Jayoon) and the life simulation game, highlighting her almost too-perfect appearance
Baby Tiger: Reflects contrasting aspects of her personality
Yoonja: An endearing nickname used by fans

The "Human Sims" moniker particularly resonates because, as fans note, Yoon "looks as perfect as a computer graphic character". Her unique combination of height, proportions, and distinctive features creates an almost unreal quality that fans find captivating.

Consequently, when discussing STAYC's visuals, Yoon consistently ranks among the top members in terms of popularity, typically placing first or second in direct cam view counts.

Surprising Hobbies and Talents

Underneath the polished K-pop idol exterior, Yoon possesses several unexpected talents and hobbies that reveal her multifaceted personality. These surprising interests showcase a side of her that fans rarely glimpse during typical STAYC performances and appearances.

Gaming and console setup

Yoon's passion for gaming stands out among her leisure activities. She particularly enjoys competitive games, with Overwatch ranking as one of her favorites. This team-based shooter allows her to demonstrate strategic thinking and quick reflexes—skills that undoubtedly benefit her performance capabilities as well. Alongside Overwatch, she frequently plays Kart Rider, a racing game popular throughout South Korea.

Unlike some casual gamers, Yoon approaches gaming with the same dedication she brings to her musical career. Her gaming hobby provides a welcome respite from her demanding schedule as an idol, offering both entertainment and a way to unwind after intense practice sessions or performances.

Excel certification and woodworking interest

Remarkably, Yoon obtained a certificate of proficiency in Microsoft Excel during her elementary school years. Even as this certification has since expired, it demonstrates her early interest in developing practical skills beyond the entertainment sphere. This technical proficiency hints at her analytical abilities and attention to detail.

Even more surprisingly, Yoon has expressed that if she hadn't become an idol, she likely would have pursued a career related to woodworking. This unexpected career alternative reveals her appreciation for craftsmanship and hands-on creation. Supporting this interest, she has demonstrated exceptional skill at assembling furniture and handling tools—practical talents that contrast with her public image as a vocalist and performer.

Talking in her sleep

As a testament to her energetic nature extending even into unconsciousness, Yoon is known to talk in her sleep. This peculiar habit adds to her endearing quirks and has likely provided amusing moments for her fellow members during their shared living arrangements. Sleep talking often reveals subconscious thoughts, making this an intriguing glimpse into her unfiltered personality.

Beyond these primary interests, Yoon possesses additional unexpected talents. She excels at solving mystery quizzes, demonstrating keen analytical thinking and deductive reasoning. This ability to quickly identify patterns and solutions translates well to her role in STAYC, where adaptability and quick thinking are essential skills for navigating the constantly evolving K-pop industry.

Yoon’s Favorite Things

Like many K-pop idols, Yoon's personal preferences reveal another dimension to her character beyond her professional persona. From culinary delights to musical inspirations, these favorites offer fans deeper insight into the STAYC vocalist's authentic self.

Favorite foods and snacks

When it comes to cuisine, Yoon gravitates toward comfort foods with bold flavors. Among her most cherished dishes is tteokbokki, the spicy rice cake dish beloved throughout Korea. This preference for spicy food extends to her enjoyment of kimchi jjigae, a traditional stew that showcases her appreciation for classic Korean flavors.

For breakfast, Yoon often chooses cereal—a simple yet practical choice that accommodates her busy schedule as an idol. In contrast to these everyday selections, she has mentioned enjoying more elaborate meals like samgyeopsal (grilled pork belly) during group outings and special occasions.

As for snacks, Yoon particularly enjoys:

Fruit-flavored candies
Chocolate cookies
Various Korean street foods, especially hotteok (sweet pancakes)

Her sweet tooth frequently emerges during STAYC's behind-the-scenes content, where she can often be spotted enjoying desserts between practice sessions or performances.

K-pop idols she admires

Throughout various interviews, Yoon has expressed admiration for several senior artists in the industry. Most prominently, she looks up to Hwasa from MAMAMOO, whose bold stage presence and distinctive vocal style align with qualities Yoon strives to develop in her own performances.

Alongside Hwasa, Yoon respects Sunmi for her longevity in the industry and evolution from group member to successful soloist. This admiration hints at Yoon's potential interest in eventually pursuing solo activities alongside her STAYC commitments.

Male artists feature in her list of respected seniors as well, with SHINee's Taemin standing out for his exceptional dance skills and artistic growth throughout his career—qualities that resonate with Yoon's own development as a performer.

Dream collaborations

Looking toward future opportunities, Yoon has expressed enthusiasm about potential collaborations both within and beyond the K-pop industry. First, she has mentioned Little Mix as her dream international collaboration, appreciating their powerful vocal harmonies and empowering concepts that align with STAYC's own musical direction.

Within the domestic scene, Yoon hopes to someday work with (G)I-DLE, particularly citing their self-produced music as an inspiration. This preference reveals her interest in potentially participating more actively in STAYC's creative process moving forward.

Furthermore, Yoon has expressed interest in exploring different musical genres through collaboration, specifically mentioning R&B as a style she would like to experiment with more extensively than STAYC's current discography allows.

Solo Activities and Web Shows

Outside of her group activities, Yoon has built an impressive portfolio of solo ventures that showcase her versatility as an entertainer. These individual projects have helped establish her distinct identity within the competitive K-pop landscape.

Curious Jayoon series

The self-produced "Curious Jayoon" web series stands as Yoon's most popular solo content. The first season launched in 2023, featuring Yoon investigating unusual questions across ten episodes. After its success, Season 2 premiered in October 2024 with weekly Friday releases.

"It doesn't feel real that a year has passed," Yoon reflected about the show's return. The second season explores intriguing curiosities such as "How much would it cost if I stayed at a pension alone?" and "Is the calorie consumption displayed on a treadmill accurate?"

Recent episodes have featured Yoon investigating whether bees exist in honeycomb toppings and experiencing hypnosis to explore past lives—where she discovered she might have been "Charlie," a seven-year-old boy living in a British port city in 1873.

Radio DJ and MC roles

Alongside her web content, Yoon has expanded into broadcasting. She served as a radio DJ for a three-week period in March 2023 and has made special MC appearances on programs like SBS's "Inkigayo".

In January 2025, Yoon took a significant career step by joining the cast of Coupang Play's office comedy series "Office Workers." Based on the popular "SNL Korea" segment "MZ Office," the show features Yoon as an enthusiastic maknae employee working alongside veteran performers like Shin Dong Yup.

Brand endorsements and vlogs

Merely five months after STAYC's debut, Yoon secured an endorsement deal with LG Household & Health Care, becoming the face of beauty brand "Code Glokolor" alongside groupmates ISA and Sumin.

Between official schedules, Yoon has produced personal vlogs documenting her daily life and travels. Her first vlog captured a vacation in Jeju, offering fans a glimpse into her personality outside structured performances. Additional content includes dance covers of songs by Red Velvet and Avril Lavigne, further demonstrating her artistic range beyond STAYC's repertoire.