It was the first time in his 30-year acting career that Joo Sang-wook played a full-fledged villain. Long known for his gentlemanly and warm screen image, the veteran actor shed that persona to portray a ruthless, unhinged antagonist, winning praise from viewers.

SBS' Friday-Saturday drama "Agent Kim Reactivated," which concluded on July 25, wrapped up with a nationwide viewership rating of 23 percent, according to Nielsen Korea. The series stood out at a time when TV dramas across terrestrial, cable and general programming channels have struggled to attract audiences.

Speaking in an interview before the finale, Joo said, "I never expected it to become such a huge hit. The director told me this project would be a turning point in my acting career, and that's exactly what happened. It feels wonderful to experience this kind of success again."

The drama also found a global audience. According to Netflix's official Tudum website, "Agent Kim Reactivated" topped the Global Top 10 chart in the non-English TV category for three consecutive weeks.

Asked whether he has felt the impact of the show's popularity, Joo said, "I've noticed a big increase in comments on my social media, so it's gradually sinking in. Not only overseas, but the response around me has completely changed. People recognize me wherever I go, and I've received many congratulatory messages. I think that's the power of 'Agent Kim Reactivated.'"

Joo credited the show's success to its entertainment value.

"I believe the most important thing for any drama is that it's fun. Artistic merit only matters after you've succeeded in entertaining the audience," he said. "'Agent Kim Reactivated' was a drama that never gave viewers a chance to get bored. The satisfying sense of justice and revenge, along with many other elements, came together to make it such a beloved series."

Joo played Ju Kang-chan, a construction company chairman and former hired thug, portraying everything from the cold charisma of a powerful businessman to twisted fatherly love, emotional vulnerability and obsessive madness.

To prepare for the role, he lost 7 kilograms while increasing his muscle mass.

"My first scene was in a sauna, so I was really worried," he said with a laugh. "I started working out twice a day three months before filming began. It was the strictest diet and fitness routine I've ever followed. I checked my weight and physical condition every day to create Ju Kang-chan's appearance."

Because it was his first major villain role, he also devoted significant effort to understanding the character.

"Even from an actor's perspective, he was someone who was difficult to understand on a human level," Joo said. "So I tried to approach everything entirely from Ju Kang-chan's point of view. In particular, the scene where he commits a crime against Golden Teeth (Cho Bok-rae) best captures who he really is. I didn't see him as simply frightening, but as someone who had absolutely nothing to fear."

In the latter part of the drama, Ju is thoroughly defeated by Manager Kim, played by So Ji-sub, in an intense action sequence.

"That scene took an entire day to film. I spent more than 10 hours just getting beaten up," Joo recalled. "Rather than worrying about how to get hit, I focused on making it look as realistic as possible."

He added, "So Ji-sub is one of Korea's top action actors, so we rehearsed extensively, and he taught me a lot. Even so, I could barely move the next day. My neck was so stiff I couldn't even turn my head. But it was rewarding to know viewers found the scene satisfying."

Buoyed by the drama's success, discussions are underway about producing a second season.

"I'm disappointed that Ju Kang-chan probably won't be part of it," Joo said. "But I also expect an even more powerful villain to appear. I'm looking forward to Season 2 as a viewer."

Behind Ju's crimes lies his distorted paternal love. As a father to a daughter himself, Joo reflected on the character's motivations.

"I think every father feels the same way. We'd do anything for our daughters," he said. "Manager Kim and Ju Kang-chan probably shared that feeling. The methods were completely different, but at the core, they were both driven by fatherly love."

Joo married actress Cha Ye-ryun in 2017, and the couple has a daughter.

Asked how his wife reacted to the show's success, he said, "She's not the type to openly shower me with compliments, but I can always feel her support. As an actress herself, she knows how difficult it is to come across a project that receives this kind of response, so I think she's happier than anyone for me."

Joo concluded by saying, "People have always had a certain image of me, but I'm grateful that this drama allowed me to show a completely different side of myself. 'Agent Kim Reactivated' will remain a turning point in my acting career for a long time."

This article from the Hankook Ilbo, the sister publication of The Korea Times, is translated by a generative AI system and edited by The Korea Times.