Meet Jason Yu, the Promising New Director Mentored by Bong Joon-ho

South Korean director Jason Yu had gone three decades without experiencing any recurring nightmares. Then his movie got into Cannes, and a month’s worth of bad dreams began. The nightmares involved a filmmaker’s worst fear: finding out that people hate your work. In his dreams, a sales agent would enter some sort of greenroom after a screening and tell Yu that it hadn’t gone well. She’d try to console him, insisting that only the movie’s Korean audience mattered anyway. But the disappointment would linger after Yu woke, like the dream had actually happened—over and over and over.

The nightmares kind of made sense, though. Yu’s movie, Sleep, is about a newlywed (Parasite’s Lee Sun-kyun) who develops a perilous sleepwalking habit while his wife (Jung Yu-mi) is pregnant with their first child. And fortunately for the 34-year-old debut director, who was mentored by Palme d’Or winner Bong Joon-ho, his Cannes reception was no nightmare. Sleep garnered more and more attention at festivals around the world throughout 2023 and 2024. At the same time, it became an, ahem, sleeper hit in Yu’s home country, knocking Oppenheimer from the top spot at the Korean box office last September. It has since opened in more than a dozen other territories.

Yu’s film enters the last phase of its long rollout on September 27, when it finally opens in select American theaters. Sleep is primarily a tense horror thriller with a central mystery: What’s causing this guy’s sudden nighttime chaos? But it’s also a dark comedy about parenthood, careerism, mysticism, and urban life where your downstairs neighbors can hear your every move. Most importantly for Yu, it’s about marriage, a topic that he feels tends to produce “cynical” films.

“I wanted to have a more romantic view, and I wanted to portray a couple that were best friends, who really supported each other, who really loved each other, and maybe throw an external obstacle their way just to see how they would overcome it as a married unit,” he told Vanity Fair over breakfast at Fantastic Fest in Austin last year. “Looking back, that was the thing I was more excited about compared to the horror elements of the film.”

Yu came to filmmaking as a university student who initially thought he might become a lawyer. Then a creative writing professor exposed him to contemporaneous prestige films like There Will Be Blood and No Country for Old Men. Yu was hooked. While completing the military service required of able-bodied Korean men, he spent as much time as possible watching movies. In the barracks, his friends labeled him “the film guy” and encouraged him to pursue his new passion. After Yu was discharged, the military set him up with a gig as an assistant director on the 2013 Korean blockbuster Secretly, Greatly. He loved the experience, returning to school determined to make a career out of it.

Eventually, that led him to Bong—specifically Okja. Yu answered a listing that sought an assistant director with prior set experience and reliable English skills. He had lived on and off in the United Kingdom while growing up and, although he sometimes insists otherwise, speaks fluent English.

In the Korean film system, assistant directors are jacks-of-all-trades. Yu scouted locations in the countryside, auditioned actors for minor parts, served as a sort of script supervisor during postproduction, and, most consequentially, became Bong’s translator. He would speak to the film’s American and British cast and crew on Bong’s behalf, and he attended press events throughout the movie’s release. (Before Sharon Choi, the internet-beloved interpreter who translated for Bong during the Parasite awards season, there was Jason Yu. Choi attended Sleep’s Korean premiere last year, where she and Yu met for the first time.) Yu then wrote subtitles for other films, including 2018’s Burning, and soon enough had finished a script of his own, written as he was preparing to marry his longtime girlfriend.

As things worsen for Sleep’s husband character, Hyeon-soo, his wife, Soo-jin, seeks a solution. Hyeon-soo’s sleepwalking is turning violent, so they try meds. Then they give wacky shamanistic rituals a shot, because maybe he’s possessed. When his wife gives birth, Hyeon-soo temporarily moves out so as not to harm the baby. But that’s no way to sustain a relationship, and as the couple reunites, Sleep hurtles toward a nail-biting, somewhat ambiguous finale. When Bong read Yu’s Sleep script, and after he watched the final film, he had one major piece of advice for his protégé: Don’t explain the ending. Instead, let people arrive at their own conclusion. Bong later called Sleep “the most unique horror film and the smartest debut film I’ve seen in 10 years.”

“In Q&As, I get asked a lot about how to interpret the ending,” Yu says. “[Director Bong] realized that a lot of the time the audience members come up with their own interpretations. That’s a kind of secondary joy to have after watching a film. And [Bong] said, ‘You don’t really want to close the door on it.’”

Given the film’s sense of humor and Yu’s optimistic views on marriage, it makes sense that he’d like to make a romantic comedy one day. Those are some of his favorite kinds of movies, No Country for Old Men be damned. For now, though, he’s recharacterizing the nightmares that Cannes foisted upon him, realizing that even if Sleep hadn’t become a global indie darling, he still achieved his dream. As Yu says, “I would have been very lucky if I just completed the film—and it bombed.”