As a teenager, Fukunaga became obsessed with the Civil War. When a janitor at his Sebastopol, Calif., high school handed him a flier for a Civil War re-enactment, he went. He became a re-enactor himself, falling in with a crowd that was particularly devoted to realism; they would soak bits of their costumes in urine and excrement and try to be as historically accurate as possible. “There’s this thing in re-enacting called ‘having a moment,’ ” Fukunaga says, “when there’s nothing around you that indicates that you’re living in 2018. You look left, and there’s 6,000 people that way, and you look right, and there’s 6,000 that way, and there’s no audience. The present tense sort of dissolves, and you really feel this sort of transcendental experience of being this other person. Sometimes you actually feel fear.”

“Having a moment” is the Rosetta Stone for Fukunaga, who uses his extreme, gnarly attention to material detail to vertiginously recreate the lived experience of people who are superficially nothing like him. Fukunaga spent his formative years growing up around Berkeley’s Telegraph Avenue, “surrounded by Berkeley protesters and communist bookstores and homeless people.” His Japanese-American father and Swedish-American mother divorced when he was 4, and he split time between them. His parents changed jobs with some frequency — his father worked for a generator company before eventually becoming an administrator at the University of California, Berkeley, and his mother was a dental hygienist before going back to school to become a teacher. Fukunaga spent time living in Mexico after his mother married a Mexican-American, which is how he learned to speak Spanish. He started making videos, like one about pirates, when he was 10. In his late 20s, after snowboarding for a few years and working on music videos, he went to film school at N.Y.U. His award-winning student film, “Victoria Para Chino” — a 13-minute Spanish-language short based on a 2003 news story about a tractor-trailer smuggling almost 100 immigrants across the border, found abandoned with 17 dead people inside — led directly to “Sin Nombre.”

There is something fundamentally athletic about Fukunaga’s directorial approach, the idea that with enough practice, research and experience, mastery becomes indistinguishable from instinct. His third feature film, “Beasts of No Nation,” about a child soldier — for which Fukunaga did years of research, including visiting Sierra Leone in 2002, at the end of the civil war there — was filmed in Ghana, where Fukunaga and other members of the crew came down with malaria. He shot the film himself anyway. Fukunaga explained to Idris Elba, one of the film’s central actors, the virtues of doing your own cinematography, ultimately inspiring Elba to learn how to operate a camera for his own directorial debut. “When he’s looking down the iris of the lens,” Elba says, “he can spot things, his intuition takes his eye and he can adapt right on the spot.” Working on “True Detective,” Matthew McConaughey made Fukunaga a T-shirt with the image of feet on a skateboard that said “Everything Lends,” a reference to his ability to find inspiration on the fly.

Fukunaga’s immersive tendencies extend to his hobbies, of which he has a shocking number. He skateboards, surfs, rides a motorcycle and used to practice capoeira. He lives in the West Village, but has a house in upstate New York, a two-hour drive outside the city, where he goes to relax and work in his wood shop, spending time alone or with friends. His polo horse is stabled nearby. He learned to ride after working on “Jane Eyre,” prohibited for insurance reasons from taking lessons with the cast. Because Fukunaga does not do things in half-measures, this somehow led to his becoming a devoted polo player. Trudie Styler, who appears in “Maniac” and is a friend of Fukunaga’s, says her husband, Sting, has described him as a “10,000-hour guy,” a reference to Malcolm Gladwell’s notion of the amount of time needed to master a craft. He’s the type of person who will put in the effort and “become not only proficient, but an aficionado,” she explains.

If this conjures some sort of swaggering John Huston with a snowboard, please let me clarify: Fukunaga is a distinctly Bay Area variation on the type, not macho so much as open-mindedly omni-competent. Yes, at some point, he and some buddies decided to learn as many skills as they could to survive the apocalypse — he’s not a prepper; it was more of a merit-badge thing — so he can sail a monohull, climb rocks, shoot a gun, use a bow and arrow and navigate with a compass. But he also has gorgeous handwriting, speaks several languages and loves many a lifestyle Instagram account. He just got a new cooking range upstate, the same kind as a French cook and lifestyle guru he follows, and he is thrilled about it: “It’s going to be sick. It’s wide, two ovens — you can do meat and your potatoes at the same time, your root vegetables.” He has seen a therapist. He may or may not currently be single (“sort of ... it’s complicated”), but has a reputation for falling madly in love. “The guy is a sensitive guy,” says Mick Casale, a friend and former screenwriting teacher of his at N.Y.U. “He comes over for lunch, and we just talk about love!”

“There’s an interesting juxtaposition between his personal self and his professional self,” says the director and actor Joshua Leonard, a close friend of Fukunaga’s. The two met when they both had short films at the Sundance Film Festival in 2005. “Cary is very different as a friend than he is as a director. As a friend, he is a big softy. As a director — I want to be very careful how I say this, and I want you to be careful if you use this quote — I don’t think he gives a [expletive] if people like him or not on set.”