2009–2016: Beginnings in theatre Kim made his professional stage debut in 2009 in the open-run production of
New Boeing Boeing, He reprised this role in 2013 and 2014. After graduating with his bachelor's degree in 2011, In 2012, he portrayed
Dr. Watson in Han Jae-hyeok's
Sherlock: The Secret of Birlstone, a Korean adaptation of
Sir Arthur Conan Doyle's novel
The Valley of Fear. In December 2013, he took the leading role in Park Jung-in's ''Words I Couldn't Say for 7 Years'' at the Daehakro Moonlight Theater, Seoul, later reprising this role in 2014 at venues in
Ulsan,
Daejeon, and
Busan. In autumn 2014, Kim was triple-cast as Lee Kyung-min in season 10 of Aligator Theater Company's
Rooftop House Cat after winning an audition against 200 candidates. In 2015, he secured another lead role in the company's romantic comedy
Purpose of Love. Later that year, Kim continued his work with the Aligator Theater Company while transitioning to a darker repertoire, auditioning for
Oh Man-seok's revival of
Sam Shepard's
True West. Kim was triple-cast as Austin alongside
Lee Hyun-wook and Moon Sung-il, alternating performances opposite
Jeon Seok-ho, Kim Jun-won, and Lee Dae-il, who shared the role of Austin's brother, Lee. The production ranked first in
Interpark sales as soon as bookings opened. To close out the year, Kim took on the role of Valentin in Moon Sam-hwa's revival of
Kiss of the Spider Woman, performing in the
Manuel Puig two-hander from November through January 2016. In 2016, Kim auditioned for Theater Ganda's production of
John Cariani's
Almost, Maine. Despite a 200-to-1 competition rate, he secured a place in the production and portrayed four different roles as part of the second cast, beginning his run in April. He followed this with two consecutive productions with Aligator Theater Company: first reprising the role of Austin in the Korean encore of
Sam Shepard's play
True West Return and subsequently performing in the revival of
Patrick Marber's
Closer. Directed by
Roh Deok, the latter featured Kim alongside an ensemble including
Bae Seong-woo,
Seo Hyun-woo,
Kim So-jin, and
Park So-dam. In November, he joined the production of Park Dong-wook's
Voice of Millennium. The play was produced by Space to Create and directed by Park Seon-hee. Kim's rising prominence in
Daehakro during this period earned him the nickname "theater idol." In a year-end review, critic Huh Yun-seon recognized Kim as an actor with significant potential, highlighting his "explosive energy" on stage.
2017–2019: Television debut Kim debuted on screen in early 2017, playing accounting department employee Seon Sang-tae in the
KBS2 office drama
Good Manager. Kim followed this with the
MBC action comedy
Two Cops, starring opposite
Jo Jung-suk and
Lee Hye-ri. Director Oh Hyun-jong cast him as the second lead, conman Gong Su-chang, despite Kim originally auditioning for a supporting role. For his performance, Kim won both the
New Actor Award and the Excellence Actor Award at the
2017 MBC Drama Awards. While the series was still airing, he reprised his stage role as Valentin in an encore production of
Kiss of the Spider Woman. In May, 2018, Kim starred in his main
protagonist role in the four-episode
MBC drama
You Drive Me Crazy. Portraying painter Kim Rae-wan alongside
Lee Yoo-young, the production was noted for the lead actors' chemistry and topped portal site search rankings during its broadcast. Concurrently, Kim had been filming his first
pre-produced historical drama,
100 Days My Prince, since April. In the series, he portrayed Jung Jae-yoon, a genius
yangban with
prosopagnosia, whose career rank is limited by his status as the illegitimate son of a
concubine. from September 10 to October 30, 2018, it peaked at 14.4% viewership, becoming one of the
Korea's highest-rated cable dramas. It led
Good Data's TV Drama Buzz-worthiness rankings for three weeks, with Kim ranking sixth among performers in mid-October. Later that October, Kim starred opposite
Moon Geun-young in the
tvN investigative crime drama
Catch the Ghost. He portrayed Go Ji-seok, a
subway police detective who sacrificed a career in the
violent crimes unit to care for his mother following her
dementia diagnosis. This project marked his second main protagonist role in a full-length series following
Welcome to Waikiki 2. On November 5, 2019, Kim joined the permanent cast of the fourth season of the
KBS2 reality show 2 Days & 1 Night. His work on the program earned him the Rookie Award at the
2020 KBS Entertainment Awards. For his final project of the year, Kim returned to the stage in the play
Memory in dream. During his run from November 2019 to February 2020, he performed in 33 sold-out shows, attracting an audience of approximately 4,700.
2020–2022: Breakthrough roles In March 2020, Kim made a special appearance in the
MBC drama
Find Me in Your Memory, which served as a reunion with
Two Cops director Oh Hyun-jong and his
Welcome to Waikiki 2 co-star
Moon Ga-young. Later that year, Kim appeared in television series
Start-Up, written by
Park Hye-ryun and directed by
Oh Chung-hwan. Aired concurrently on
tvN and
Netflix from October 17 to December 6, 2020, it starred Kim alongside
Bae Suzy,
Nam Joo-hyuk,
Kang Han-na and
Kim Hae-sook. His role as
Han Ji-pyeong, a self-made
venture capitalist who succeeded after
aging out of the foster-care system, drew positive reviews and raised his profile both at home and abroad. During the series' run, he stayed in
Good Data's Top 10 Actor Buzz-worthiness for six straight weeks, peaking at third, and led the Korean Business Research Institute's Actor Brand Reputation ranking in November. He then featured on the 2021
Forbes Korea Power Celebrity 40 list. He went on to win the
Most Popular Actor Award at the
57th Baeksang Arts Awards, where he was also nominated for
Best Supporting Actor – Television. The character was later named one of the Characters of the Year at the 2021
Seoul International Drama Awards. The Beautiful Foundation praised the character for challenging media stereotypes surrounding
youth aging out of foster-care; this led the organization to send handwritten letters and gifts to
Studio Dragon and Kim, noting that, "Kim Seon-ho has brought the character to life with his excellent acting." He then returned to the theater with
Jang Jin's
two-hander Ice from January 8 to March 21, 2021 at S Theater,
Sejong Center for the Performing Arts, playing Detective Lee Jong-ryeol. All his shows sold out on the first day as tickets went on sale. He and actor
Jung Woong-in reprised their roles for a special encore performance on May 16 at the
Seongnam Arts Center. Earlier, on May 8, Kim released the single "Reason" for his fans. He co-wrote the lyrics with
Epitone Project, marking their second collaboration after he previously starred in one of his music videos. In August 2021, Kim
headlined the
tvN romantic comedy series
Hometown Cha-Cha-Cha, opposite
Shin Min-a, playing a multi-skilled handyman and village chief
Hong Du-sik. For the part, Kim learned to surf, trained as a
barista, and practiced guitar so he could perform "Old Love" by
Lee Moon-sae in the series. Critic Matt O'Neill wrote in a review that the on-screen chemistry between
Shin Min-a and Kim "is akin to that of
Julia Roberts and
Richard Gere in
Pretty Woman." The series achieved peak ratings of 13.3%, among the
highest recorded for cable drama. It spent 16 weeks on Netflix's Global non-English Top 10 list, reached the Top 10 in over 20 countries, and remained on global charts for two months post-finale. Kim secured first place in
Good Data's "Drama Performer Buzzworthiness" list for five straight weeks, and was named
Gallup Korea Television Actor of the Year. He went on to win the Outstanding Actor Award at the 2022
Seoul International Drama Awards. Filming for his debut feature film,
The Childe, started in December 2021, with overseas scenes filmed in Thailand in March 2022. In mid-2022, Kim returned to the stage for the third installment of
The 9th Best Plays Festival in the Korean premiere of
David Greig's play
Touching the Void. Directed by
Kim Dong-yeon, Kim was triple-cast in the role of
Joe Simpson with
Shin Sung-min and
Lee Hwi-jong. All of Kim's performances, which ran from July to September 2022 in the 250-seat Art One Theater, sold out according to
Interpark. He donated his entire theater fee to
Typhoon Hinnamnor relief. along with Best Theater Actor nomination at in April 2023.
2023–2024: Film debut, theater work, and return to television 2023 saw him work on two primary projects, beginning with
Park Hoon-jung's
The Tyrant, which filmed from January 2 through April. From June to November, Kim filmed the
streaming series Unfriend. During this period, Kim also promoted his feature film debut,
The Childe, which opened in South Korea, Taiwan, and Indonesia on June 21, 2023, before its subsequent worldwide release. Kim portrayed (lit. nobleman), an eccentric
killer-for-hire. As requested by director Park Hoon-jung, Kim modeled his character after
Stanley Kubrick's
A Clockwork Orange. His preparation involved two months of English practice and intensive action training including
firearms handling. Despite his
acrophobia, Kim performed most of his own stunts, including a jump from an
overpass. Critic James Marsh of
South China Morning Post noted that the nobleman exhibited "self-effacing irreverence". For his performance, Kim won the Best New Actor award at both the
Buil Film Awards and the
59th Grand Bell Awards. At the
44th Blue Dragon Film Awards in December 2023, he was nominated in the Best New Actor and also received the Chung Chung Won Popular Star Award. The following year, he earned nominations for Most Popular Actor and Best New Actor at the
60th Baeksang Arts Awards. as Lee Eun-soo. His character, originally named Eden, was localized to Korean as Kim Woo-jin. On October 20, 2023, Content Haap announced that Kim would be triple-cast in this role alongside , and
Ahn Woo-yeon. The play ran from December 5, 2023, to February 18, 2024, with all performances featuring Kim selling out. Kim reunited with
Welcome to Waikiki 2 co-star
Moon Ga-young for
Daesung's music video "Falling Slowly," directed by
Hong Jong-chan. The video was released on March 5, 2024. Following this, Season 2 of
Mukbo Brothers premiered on March 25 on
SBS Plus, marking Kim's return to
variety television and his reunion with
2 Days & 1 Night co-star
Moon Se-yoon. The first four episodes followed Kim as he toured
Chiang Mai and
Chiang Dao, including a visit to
Elephant Nature Park to meet
Sangduen Chailert and her elephants. On April 8, 2024, Kim met with 600 fans during a special pre-release stage greeting for The Childe in Tokyo, alongside journalist . To coincide with the official Japan premiere on April 12, cinemas in Marunouchi Piccadilly, Shinjuku, and Osaka's
Namba Parks began displaying the original nobleman costumes actually worn by Kim during filming. During this period, Kim also released "Miracle", a digital single dedicated to his fans on April 30 on various music platforms. He co-wrote the song with lyricist Kim Ji-hyang. The song was first performed live in Bangkok in February 2024, during his tour, followed by performances in Osaka, Tokyo, Manila, Seoul, and Jakarta. On August 14, 2024,
The Tyrant premiered on
Disney+, marking the first
streaming series for Kim and director
Park Hoon-jung. Originally developed as a film, its reformatting into a four-part series was announced on February 19.
Promotional activities featuring Kim alongside
Cha Seung-won,
Kim Kang-woo, and
Jo Yoon-su, were held in July and August ahead of the release. In the series, Kim portrays Director Choe, the youngest leader of
South Korea's National Intelligence Service, who oversees a clandestine unit running the Tyrant Program. To prepare for this role, he drew inspiration from
Tinker Tailor Soldier Spy and
Peaky Blinders, losing seven kilograms to match his character's haggard appearance and practicing smoking for three months despite being a non-smoker. Critic Carmen Chin praised Kim's performance, noting his "aloof yet grounded charisma that feels incredibly natural." His portrayal earned him nominations for Popular Male Actor Award and Best Male Actor in a Short Film/Web Drama at the
2024 APAN Star Awards, and he won Outstanding Asian Star at the 2025
Seoul International Drama Awards.
2025–present: Agency changes, streaming series and return to theater In February 2025, Kim became a free agent before signing an exclusive contract with
Fantagio the following month. In March 2025, Kim made a special appearance in writer
Lim Sang-choon's Netflix series
When Life Gives You Tangerines, as
Park Chung-seop, husband of Yang Geum-myeong (
IU). Director
Kim Won-seok noted that while Chung-seop becomes significant later in the series, he is not central to the main narrative. Despite the limited screentime, Kim ranked tenth in
Good Data's "TV-OTT Drama Performer Buzzworthiness" list in the third week of March, and rose to third place the following week. Chung-seop's wedding scene initiated the "Kim Seon-ho Smile Challenge" on Chinese social news, garnering over 170 million views on
Douyin and 1 million likes on
Xiaohongshu. A
TikTok edit featuring
Ariana Grande's song "Supernatural" went
viral with over 22 million views and more than 2 million likes, encouraging further participation in the challenge. This prompted Grande to share a compilation of the challenge videos on her own social media accounts. Kim returned to the romance genre with
Netflix original series
Can This Love Be Translated?, written by the
Hong Sisters. On the series' release date, January 16, 2026, Kim, co-star
Go Youn-jung, and director
Yoo Young-eun attended an promotional event in Jakarta, Indonesia. In the series, Kim portrayed Joo Ho-jin, a
multilingual interpreter whose life becomes intertwined with top actress Cha Mu-hee, played by Go. To prepare for the role, Kim observed professional
interpreters and completed four months of intensive Japanese, Italian, and English language courses; language coaches were also present on set to assist during filming. Filming took place from June 2024 to February 5, 2025, and spanned numerous locations across South Korea, Japan, Canada, and Italy. Kim returned to the stage in the
two-hander play
Secret Passage: Interval. Directed by
Min Sae-rom, this adaptation of
Tomohiro Maekawa's
Loophole Conference Room featured Kim as Dong-jae, a role requiring him to portray various reincarnated versions of the character. The play runs from February 13 to May 3, 2026 at the Nol Theater. Concurrently, Kim was also filming for the
Disney+ series
Portraits of Delusion. Directed by
Han Jae-rim and based on
Hongjacga's
manhwa Delusion, the series reunited Kim with his
Start-Up co-star
Bae Suzy. Following a filming cycle that began in May 2025, the drama is scheduled to premiere in the second half of 2026. His upcoming project also includes the crime mystery series
Unfriend, which is slated to premiere as a
TVING original. Though filmed in 2023, the series, co-starring
Park Gyu-young, was held for a 2026 launch. Co-directed by
Kim Jee-woon and
Park Bo-ram, the project is a joint production by Yong Film, Anthology Studio, and SK Global Entertainment, adapting
Chan Ho-kei's crime novel
Second Sister. == Other ventures ==