Saying Yoo Yeon-seok is a versatile actor is an understatement. He has been honed by his long list of diverse projects into becoming a well-rounded actor who could portray any role that comes his way. His numerous TV and movie projects are also a testament of how tough it was for him to climb out of obscurity and continue despite the lack of appreciation. But being a top actor was really in his fate as he finally stumbled the right role that catapults him into his present popularity.
Without further ado, let’s look at the 17 years of Yoo Yeon-seok in the Korean Entertainment industry.
Oldboy | (Movie / 2003) – Woo-jin (young)
Debuting in 2013, he acted as the young version of Yoo Ji-tae’s character, Lee Woo-jin, in the critically acclaimed neo-noir action thriller film, Oldboy.
Fun fact: One of his friend from acting school told him he has resemblance with actor Yoo Ji-tae. The same friend was the one who told him about the child actor audition for the movie.

Chosun Police 2 | (MBC / 2008) – Victim’s Husband
After finishing his degree in Film Arts at Sejong University, he finally returned to the K-ent industry and started using his stage name Yoo Yeon-seok (real name: Ahn Yeon-seok). His first TV apperance is in MBC’s sageuk drama Chosun Police 2.

General Hospital 2 | (MBC / 2008-2009) – Heo Woo-jin
His official drama debut was through a supporting role in the MBC’s General Hospital 2, which was topbilled by Cha Tae-hyun and Kim Jung-eun.
Fun fact: In his pre-production interview for Hospital Playlist, Yoo Yeon-seok shared how he prepared for his first medical drama but he didn’t get any line with medical terms.

Dream | (SBS / 2009) – No Chul-joong
He continued getting supporting roles for TV dramas including this SBS series, Dream.

Soul | (MBC / 2009) – Baek Joong-chan
In the horror TV series, Soul, Yoo Yeon-seok played the role of obnoxious student body president, Baek Joong-chan.
Fun fact: He personally picked out the half-rimmed glasses his character wore in this series.

Running, Goo | (MBC / 2010) – Heo Ji-man
He was cast in the four-episode MBC youth drama Running Goo alongside then up-and-coming stars Park Min-young and Baek Sung-hyun.

Re-encounter | (Movie / 2010) – Han-soo
The same year, Yoo Yeon-seok finally got the chance to showcase his acting chops through his role as Han-soo in this indie movie. The coming of age movie, which also stars Yoo Da-in, premiered at the 15th Busan International Film Festival.

Pure Pumpkin Flower | (SBS / 2010) – Hyo-joon
Yoo Yeon-seok also appeared in the daily drama Pure Pumpkin Flower.

Moscow | (Movie / 2011)
Yoo Yeon-seok then took on a number of roles in both TV and Films including this film entitled Moscow.

Late Night Hospital | (MBC / 2011) – Yoon Sang-ho
Appearing in another medical drama, Yoo Yeon-seok played the role of Yoon Sang-ho in the 10-episode series Late Night Hospital.

Cats and Dogs | (Variety Show / tvN / 2012) – Host
He got his first variety show gig as the host of tvN’s Cats and Dogs.

Eighteen, Nineteen | (Movie / 2012) – Ho-ya
Starring in another youth movie, Yoo Yeon-seok take on the role of young boxer, Hoya. Eighteen, Nineteen tells the coming of age story of fraternal twins Hoya and Seoya, played by Baek Jin-hee.

Tasty Life | (SBS / 2012) – Choi Jae-hyuk
On his third medical drama, Yoo Yeon-seok played the role of Choi Jae-hyeok, a handsome doctor and son of the hospital director, in the weekend drama Tasty Life.
Fun fact: He sang Lee Seung-gi’s “Will You Marry Me” during his proposal scene with Yoo Jung-hee.

Mom is Acting Up | (MBC / 2012) – Kim Yeon-seok
He was also part of MBC family drama Mom is Acting Up (also known as What About Mom?) .

Architecture 101 | (Movie / 2012) – Jae-wook (past)
After getting appealing characters, he was then typecast in various villainous roles such as the haughty senior in box-office hit Architecture 101.
Fun fact: They didn’t have a scene together but Yeon-seok’s Hospital Playlist co-star Jo Jung-suk is also in this movie.

Two Weddings and a Funeral | (Movie / 2012) – Suk’s younger brother
He acted as Song Yong-jin’s younger brother in the 2012 movie, Two Weddings and a Funeral.

Horror Stories | (Movie / 2012) – kidnapper
He played a serial killer in the 2013 horror anthology film Horror Stories. He and Kim Ji-won was part of the outer story where the four short stories were told.

A Werewolf Boy | (Movie / 2012) – Ji-tae
He played the antagonist in the hit movie A Werewolf Boy, topbilled by Song Joong-ki and Park Bo-young.

Gu Family Book | (MBC / 2013) – Park Tae-seo
There’s no doubt 2013 is Yoo Yeon-seok’s lucky year. He finally took on roles that raised his profile as an actor and finally catapulted him into stardom. One of his roles in this year is Park Tae-seo in the fantasy drama Gu Family Book, where he reunited with his Architecture 101 co-star Bae Suzy.

Born To Sing | (Movie / 2013) – Dong-soo
Playing a lighter role, Yoo Yeon-seok was cast in the comedy drama Born to Sing.

Reply 1994 | (tvN / 2013) – Chilbong
On his 10th year in the industry, Yoo Yeon-seok was cast as the charming baseball player in nostalgic campus drama Reply 1994.

Hwayi: A Monster Boy | (Movie / 2013) – Director Park Ji-won
He was yet again in another antagonist role in Hwayi: A Monster Boy, where he got the chance to work with Kim Yoon-seok and Yeo Jin-goo.

Youth Over Flowers | (Variety Show / tvN / 2014) – Regular Cast
He reunited with Reply 1994 co-stars, Son Ho-jun and Baro in the travel reality show Youth Over Flowers.

The Whistleblower | (Movie / 2014) – Shim Min-ho
Following his breakout year, he starred in high-profile films including The Whistleblower where he played the role of biotech researcher Hwang Woo-suk.

The Royal Tailor | (Movie / 2014) – King
He worked with Han Suk-kyu, Go Soo, Park Shin-hye, and Ma Dong-seok in the period drama The Royal Tailor. His portrayal as the King got him nominations for Best Supporting Actor in the 51st Baeksang Arts Awards and the 52nd Grand Bell Awards.

Perfect Proposal | (Movie / 2015) – Sung-yeol
In 2015, Yoo Yeon-seok starred opposite Im Soo-jung in the romantic thriller film Perfect Proposal.

Warm and Cozy | (MBC / 2015) – Baek Gun-woo
Landing his first leading role for series in a public broadcasting network, Yoo Yeon-seok played the role of chef and restaurateur Baek Gun-woo who opened his restaurant in Jeju to impress his first love in this Hong Sisters penned rom-com.

The Beauty Inside | (Movie / 2015) – Woo-jin
Yoo Yeon-seok was cast as one of the actors playing Woo-jin in the star-studded movie The Beauty Inside.

Mrs. Cop | (SBS / 2015) – Jo Young-Woo (ep.16)
He made a cameo appearance in Mrs. Cop, a drama starring his good friend Son Ho-jun.

WEKID | (Variety Show / Mnet / 2016) – Judge
He also appeared in the Mnet variety show WEKID in 2016.

Love, Lies | (Movie / 2016) – Kim Yoon-woo
Yoo Yeon-seok reunited with his The Beauty Inside co-stars Han Hyo-joo and Chun Woo-hee in the period movie Love, Lies. Here, he played Kim Yoon-woo, a songwriter and producer who got himself entangled between best friends and singers Jung So-yul and Seo Yeon-hee.

Mood of the Day | (Movie / 2016) – Kim Jae-Hyun
Not every train to Busan is zombie-infested, some are love-infected instead. In this 2015 movie entitled Mood of the Day, Yoo Yeon-seok became our dream romantic male lead. His scenes with Moon Chae-won were all heart-fluttering.

A Quiet Dream | (Movie / 2016) – motorcycle man (cameo)
In the same year, he made a special appearance in the movie A Quiet Dream.

Romantic Doctor Teacher Kim | (SBS / 2016-2017) – Kang Dong-joo
He made a TV comeback in the hit romantic medical drama Romantic Doctor Teacher Kim. He played the role of skilled doctor Kang Dong-joo, who was forced to transfer to remote Doldam Hospital, where he met eccentric doctor, Teacher Kim, and reunited with his sunbae, Yoon Seo-jung.

Busted! | (Variety Show / Netflix / 2018) – Guest
He appeared in another variety show in 2018. This time for streaming site Netflix’s Busted.

Mr. Sunshine | (tvN / 2018) – Goo Dong-mae
Not one to back down from a challenge, in 2018 , he took on the role of controversial character Goo Dong-mae in Mr. Sunshine.

Coffee Friends | (Variety Show / tvN / 2019) – Regular Cast
Reuniting with his Reply 1994 co-star Son Ho-jun and Romantic Doctor Teacher Kim co-star Yang Se-jong, Yoo Yeon-seok opened a pop-up cafe in Jeju through tvN variety show Coffee Friends. They were also joined by Choi Ji-woo, who Son Ho-jun met through Three Meals A Day.

Hospital Playlist | (tvN / 2020) – Ahn Jeong-won
Years after Reply 1994, Yoo Yeon-seok was once again cast in a Shin-Lee project. In this seasonal slice-of-life drama, Yeon-seok plays pediatric surgeon Ahn Jeong-won, who finally got the chance to work with his long-time friends in one hospital. The designated drummer of Mido and Falasol wishes to follow the footsteps of his siblings and become a priest but unexpected things happened including meeting General Surgery’s resident Jang Gyeo-ul, played by actress Shin Hyun-been.

Steel Rain 2: Summit | (Movie/2020) – North Korean Supreme Guard Command Chief
Proving his versatility once again, Yoo Yeon-seok take on the role of the fictional North Korean Supreme Guard Command Chief in the action thriller Steel Rain 2: Summit. He got the chance to work with the original actors from the first Steel Rain installment, Jung Woo-sung and Kwak Do-won.

New Years Blues | (Movie/2021) – Jae-heon
He become part of the ensemble cast for the holiday movie New Years Blues. He plays the role of Jae-heon who unexpectedly met a Jin-ah (played by Lee Yeon-hee) while she’s on her trip in Argentina. The movie also features Kim Kang-woo, Yoo In-na, Lee Dong-hwi, Chinese actress Che Duling, Yeom Hye-ran, Choi Soo-young, and Teo Yoo.

Hospital Playlist 2 | (tvN / 2021) – Ahn Jeong-won
He reprises his role as the pediatric surgeon of Yulje and drummer of Mido and Falasol for the second season of Hospital Playlist. He’s character this time navigates the ups and downs of having his first romantic relationship.

[Source: 1]
*This list was originally posted on 2020. Minor revisions were made to update the actor’s filmography.