Good Boy cast and character guide: Who plays whom in Prime Video's upcoming K drama

JTBC’s new Korean series, Good Boy, will stream on Prime Video from May 31, 2025. Starring Park Bo-gum (from When Life Gives You Tangerines), the series follows a group of former athletes whose careers in sports had to end for various reasons. They later join the police forces and help catch the town’s bad guys using their unique skill sets acquired through athletic training.

The police procedural series is directed by the renowned director, Shim Na-yeon, known for The Good Bad Mother and Beyond Evil. Synopsis of Good Boy reads:

"Faced with financial struggles, short career spans, injuries, and other challenges, sports heroes become special police officers and form a rag-tag team to fight violent crime – using their unique skills acquired during their time as athletes."

Here’s a list of the cast and character guide of Good Boy.

The cast and character guide of Good Boy

1) Park Bo-gum as Yoon Dong-ju

The 31-year-old Korean actor has captured everyone’s attention with the release of When Life Gives You Tangerines earlier this year. However, that’s not the only K-drama that he is known for, as Bo-gum also appeared in several popular dramas, such as Reply 1988 and Love in the Moonlight. Both of these helped him win many accolades and even a Baeksang Award.

Bo-gum plays Yoon Dong-ju, an Olympic gold medalist boxer whose career ended after being expelled from his team, and later joined the police forces.

2) Oh Jung-se as Min Joo-young

Good Boy has a star-studded cast that also includes another renowned Korean actor, Oh Jung-se. Recognised for his role as an autistic character, Moon Sang-tae in It's Okay to Not Be Okay, Jung-se also appeared in When the Camellia Blooms, winning a Baeksang for both series. Other than that, He recently portrayed Ae-sun’s stepfather in When Life Gives You Tangerines, Yeom Byeong-cheol.

In this new Prime Video series, Jung-se will play the character of Min Joo-young, a civil servant hiding his true intentions. Jung-se’s character might be one of the main villains of the action comedy.

3) Kim So-hyun as Ji Han-na

Kim So-hyun in Good Boy | Image via Instagram: jtbcdrama

In Good Boy, Kim So-hyun’s Ji Han-na will be seen following in her father’s footsteps to become a police officer after she failed to become a successful shooter after facing setbacks caused by misunderstandings and criticism.

So-hyun is one of the up-and-coming South Korean actresses to look forward to. From hosting popular shows like MBC’s Music Core to being nominated for a Baeksang for her performance in River Where the Moon Rises, the actress has also appeared in several other dramas like Missing You and Moon Embracing the Sun.

4) Lee Sang-yi as Kim Jong-hyeon

Lee Sang-yi in Good Boy | Image via Instagram: jtbcdrama

Another popular name, Lee Sang-yi, will play Kim Jong-hyeon in Good Boy. He was a silver medalist in fencing and will now join the police forces alongside Dong-ju and Han-na, his former girlfriend.

From his action-packed role in Bloodhounds to a cheerful-natured character in Hometown Cha-Cha-Cha, Sang-yi has appeared in many other shows such as My Demon, Spice Up Our Love, and Prison Playbook, showcasing his vast talent.

5) Tae Won-seok as Shin Jae-hong

Tae Won-seok in Good Boy | Image via Instagram: jtbcdrama

Tae Won-seok will play Shin Jae-hong in Good Boy. A former discus thrower, who even won a bronze medal, is described as initially reluctant, is described as being reluctant to join the police team with the other athletes at first. However, he later becomes a part of the team to catch the dangerous criminals roaming around the city.

Won-seok has also appeared in Bloodhounds with Lee Sang-yi. His other projects include Under the Queen's Umbrella, The Player 2: Master of Swindlers, and The Tale of Lady Ok.

6) Heo Sung-tae as Ko Man-sik

Heo Sung-tae in Good Boy | Image via Instagram: jtbcdrama

Heo Sung-tae is one of the most familiar names in the Korean industry. His role as a gangster named Jang Deok-su in Squid Game was praised by many. Apart from that, he has also appeared in Beyond Evil, The Silent Sea, and Crash. Sung-tae also appeared in many popular films such as The Boys, Collectors, and Hunt.

Sung-tae’s character, Ko Man-sik, is a former wrestler who has also won a bronze medal. He will be the leader of the special police team of former athletes in the police procedural K drama.