When fans search for 5urprise Seo Kang-joon, they are often curious about the connection between the popular Korean actor and the unusual entertainment group that helped launch his career. Before becoming widely recognized for dramas such as Cheese in the Trap, Are You Human?, Watcher, When the Weather Is Fine, Grid, and Undercover High School, Seo Kang-joon was a member of 5urprise, a unique Korean actor group created by Fantagio.
Unlike traditional K-pop groups, 5urprise was formed around actors who were trained to work across acting, music, and entertainment. The group consisted of Seo Kang-joon, Yoo Il, Gong Myung, Kang Tae-oh, and Lee Tae-hwan. Their unusual concept made them an interesting part of the Korean entertainment industry and gave several members an early platform to develop their careers.
Today, Seo Kang-joon is primarily known as an actor. However, understanding his time with 5urprise provides valuable insight into how he developed his skills and built the foundation for his later success.
Who Is Seo Kang-joon?
Seo Kang-joon, whose birth name is Lee Seung-hwan, was born on October 12, 1993, in Gunpo, Gyeonggi Province, South Korea. He studied Performing Arts at Dong Seoul University and entered the entertainment industry after working as a model and participating in Fantagio’s Actor’s League talent program.
Before becoming a major television star, Seo Kang-joon went through training designed to prepare him for professional entertainment work. This included acting development as well as experience related to music and performance.
His career is particularly interesting because he did not follow the most common K-pop route. Rather than first becoming a singer and later moving into acting, he developed as an actor before becoming part of an actor-focused group.
That approach became one of the defining characteristics of 5urprise.
What Was 5urprise?
5urprise was a five-member South Korean actor group launched by Fantagio in 2013. Its members were Yoo Il, Seo Kang-joon, Gong Myung, Kang Tae-oh, and Lee Tae-hwan. The group was notable because its members were primarily trained and promoted as actors while also participating in music and group entertainment activities.
The concept was different from a conventional idol group. In a typical K-pop group, members generally debut as singers and may later pursue acting opportunities. 5urprise reversed that formula.
The members were introduced as actors who could also sing and perform.
This made the group a distinctive experiment in the Korean entertainment industry. It also allowed the members to gain exposure through different forms of content instead of relying exclusively on music releases.
Seo Kang-joon became one of the most recognizable members of the group, eventually developing a successful individual acting career.
Seo Kang-joon’s Role in 5urprise
Seo Kang-joon was not simply a member of 5urprise; he became one of the group’s most recognizable faces. During the group’s active years, he participated in acting projects, music activities, variety programs, and promotional appearances.
His early experience with 5urprise helped him become comfortable performing in front of cameras and audiences. It also exposed him to different aspects of the entertainment business at a relatively early stage of his career.
In a 2014 interview, Seo Kang-joon spoke warmly about his relationship with the other 5urprise members, describing the group as being like a family because they shared work, difficulties, worries, and successes.
That sense of teamwork was an important part of the group’s identity.
5urprise’s Acting-Based Beginning
One of the most interesting aspects of 5urprise was that the members were connected through Fantagio’s actor-development system.
The group made its early appearance through the web series After School: Lucky or Not in 2013. The project gave viewers an opportunity to see the members acting together rather than introducing them exclusively through a traditional music debut.
This approach reflected the group’s central concept: acting was at the heart of 5urprise.
Seo Kang-joon therefore gained valuable experience at a time when he was still establishing himself in the Korean entertainment industry. Working with the same group of performers across different projects also allowed the members to develop together.
Seo Kang-joon’s Early Acting Career
Seo Kang-joon’s acting career began before his rise to mainstream popularity. He appeared in projects including To the Beautiful You and Good Doctor before gaining larger recognition.
His breakthrough period came with Cunning Single Lady in 2014. His performance helped increase his visibility, and he received the Best New Actor award at the Korea Drama Awards for the role.
Around the same period, Seo Kang-joon also appeared on the popular variety program Roommate. His television appearances allowed audiences to see another side of his personality beyond scripted drama roles.
This combination of acting, variety appearances, and 5urprise activities helped him build a growing fan base.
Why Did Seo Kang-joon Become So Popular?
Several factors contributed to Seo Kang-joon’s rise.
First, he developed a recognizable screen presence. Even in supporting roles, viewers often noticed his calm appearance and expressive acting style.
Second, he demonstrated versatility. Instead of remaining associated with one particular type of character, he gradually took on different roles across romance, mystery, science fiction, and action-oriented dramas.
Third, his experience in 5urprise gave him exposure beyond conventional acting projects. He was able to develop experience in music and variety entertainment while continuing to focus on acting.
His personality also contributed to his popularity. Earlier interviews portrayed him as relatively shy and reserved rather than extremely outgoing. He explained that he preferred preparing carefully for characters and analyzing his roles before beginning work.
That thoughtful approach became part of his professional image.
Seo Kang-joon in Cheese in the Trap
One of Seo Kang-joon’s best-known early roles came in the 2016 drama Cheese in the Trap.
The series attracted significant attention, and Seo played Baek In-ho, a character whose relationship with the main characters became an important part of the story.
The role helped introduce Seo Kang-joon to a much wider international audience. It also demonstrated his ability to play an emotionally complicated character rather than relying only on his visual appeal.
For many international fans, Cheese in the Trap remains one of the dramas most closely associated with Seo Kang-joon’s early career.
From Romantic Roles to More Serious Characters
After gaining popularity through romantic and youth-oriented projects, Seo Kang-joon continued expanding his acting range.
He appeared in Are You Human?, a science-fiction romance drama that required him to portray contrasting versions of a character. The project allowed him to demonstrate a different side of his acting abilities.
He later starred in Watcher, a crime and psychological thriller. The darker tone of the series was another step away from the romantic roles that had helped establish his early popularity.
He also appeared in When the Weather Is Fine, a slower and more emotionally focused romantic drama. The series gave him an opportunity to portray a quieter character and work within a more understated story.
His later projects included Grid and Undercover High School, showing his continued interest in different genres. Seo Kang-joon’s career therefore developed from youthful supporting roles toward increasingly varied leading performances.
What Happened to 5urprise?
Although 5urprise had a distinctive concept, the group did not continue indefinitely.
The members left Fantagio after their contracts ended around 2020, and the group subsequently entered an indefinite hiatus. Seo Kang-joon moved to Man of Creation and focused primarily on his acting career.
The end of the group’s active period did not mean the end of the members’ individual careers. In fact, several 5urprise members went on to establish themselves through successful acting projects.
For Seo Kang-joon, the transition marked a clearer focus on acting.
His time in the group remains an important part of his career history, but his professional identity today is primarily that of a Korean actor.
Seo Kang-joon’s Military Service and Return
Seo Kang-joon enlisted for mandatory military service in November 2021. He completed his service and was discharged in May 2023 after serving as an active-duty soldier.
Following his military service, fans were eager to see his return to television.
His comeback became especially notable with Undercover High School in 2025, giving audiences an opportunity to see him return to the screen after his military hiatus.
His return demonstrated that his popularity had remained strong even after his time away from entertainment.
5urprise Members: Where Are They Now?
The original 5urprise lineup included five actors:
- Seo Kang-joon – Known for Cheese in the Trap, Are You Human?, Watcher, When the Weather Is Fine, Grid, and Undercover High School.
- Gong Myung – Continued building a career through television and film.
- Kang Tae-oh – Became widely recognized for his acting career, particularly through popular Korean dramas.
- Lee Tae-hwan – Continued working as an actor across television projects.
- Yoo Il – Continued his career in acting and entertainment.
The group may no longer be active, but its members have continued developing their individual careers.
This is one reason searches for 5urprise members, 5urprise Seo Kang-joon, and Seo Kang-joon 5urprise remain relevant among Korean entertainment fans.
Did Seo Kang-joon Leave Acting?
No. Seo Kang-joon’s career has continued after 5urprise.
The end of 5urprise’s activities was essentially a transition toward individual careers rather than an end to Seo Kang-joon’s entertainment journey. He continued working as an actor, took on different genres, completed military service, and later returned to television.
His career illustrates how an actor can evolve beyond an initial group identity.
For newer fans who discovered him through Undercover High School or another recent drama, learning that he was once part of 5urprise can be an interesting introduction to his earlier career.
Why Is 5urprise Still Remembered?
5urprise holds a special place in Korean entertainment history because of its unusual concept.
The group challenged the conventional separation between acting and idol entertainment. Instead of treating acting as something members pursued after becoming successful singers, 5urprise made acting central to the group’s identity from the beginning.
The concept also helped introduce talented young performers to audiences through web dramas, television, music, and variety entertainment.
For Seo Kang-joon, the group was particularly significant because it formed an important part of his development before he became an established leading actor.
Final Thoughts
The story of 5urprise Seo Kang-joon is more than a simple connection between a famous actor and a former entertainment group. It represents an unusual chapter in the development of Korean actor-idol culture.
5urprise brought together Seo Kang-joon, Yoo Il, Gong Myung, Kang Tae-oh, and Lee Tae-hwan and gave them an opportunity to develop their careers through acting, music, and entertainment.
For Seo Kang-joon, the experience became an early foundation for a much broader acting career. From his early television appearances and Cunning Single Lady to Cheese in the Trap, Are You Human?, Watcher, When the Weather Is Fine, Grid, and his post-military return in Undercover High School, he has continued to expand his range.
Although 5urprise is no longer an active group, its legacy remains connected to the careers of its former members. For fans discovering Seo Kang-joon today, looking back at his 5urprise years offers a fascinating view of where his journey began and how he developed into one of South Korea’s recognizable drama actors.