Kim Jun-han, who began his acting career in 2012 in indie films, really began to draw attention in “Anarchist From Colony” in 2017. Since then, he has appeared in various hit series, such as “Hospital Playlist” and “Anna,” as well films “The King’s Letters” (2019) and “Beasts Clawing at Straws” (2020).

It was the 2020 film that convinced Jung Woo-sung that Kim should star in his directorial debut, “A Man of Reason.”

“He first asked for my number at the wrap party for the film ‘Beasts Clawing at Straws.’ At first I was bewildered but later felt very excited. A few weeks later, he asked me to star in his film,” Kim told The Korea Herald in an interview in Seoul on Monday.

In “A Man of Reason,” Kim plays Sung-joon, the second in command of a criminal enterprise who feels anxious after the release of Soo-hyuk (Jung Woo-sung), who spent 10 years in prison in place of his gangster boss, Eung-gook (Park Sung-woong). Sung-joon is afraid Soo-hyuk will take his place, although Soo-hyuk just wants to put the gang behind him and live an ordinary life after discovering that he has a daughter.

“What’s different about Sung-joon is that he is not just a badass guy. I felt that he must have had his own reasons and life before living his life as a gangster. I could feel his loneliness, although he is always at the center of accidents and happenings throughout the film,” Kim said.

Kim said filming “A Man of Reason” made him think about the synergy he creates as an actor with the projects. He said he and Jung shared a lot in common, such as not being too dependent on looking for references.

“Before, I used to refer to others’ acting and references when I wasn’t satisfied with my own performance. But at one point, I did not look for references because I felt like I was replicating them,” the 40-year-old actor said.

“I see acting as a process of creating synergy between what’s accumulated inside me and a great story in the script – but that doesn’t mean that I don’t like watching other films or reading books,” Kim said, laughing.

For Kim, it’s critical to be prepared.

Because he debuted in the entertainment industry as a drummer in rock band iZi in 2005, many also expect him to perform on a musical stage or take on roles like a drummer or singer in films and TV dramas.

“After watching the film ‘Whiplash,’ I did imagine myself trying out for a role like that. I thought it could be fun. I heard that the actor who played the drummer Andrew actually had a musical background, " he said. "But I want to be prepared to play such a role and study acting before I just jump into it.”

The same goes for musicals, which he has been really interested in thanks to the people around him.

“I've been invited to many musicals and stage performances by friends, and I find great joy in the entire experience. But looking into it, (acting in a musical) doesn’t seem so easy for me. I’ll have to study more,” Kim said, adding that musical star Jeon Mi-do, who he co-starred with in “Hospital Playlist,” has told him that he could be a good musical actor.

“A Man of Reason” opened in local theaters Tuesday.