A period portrait of the disintegration of a marriage as observed by the couple’s teenaged son, “Wildlife” represents actor Paul Dano’s debut as a director, and while visually it’s somewhat affected, despite a chilly surface it’s also emotionally affecting.

The stars of the film are Carey Mulligan and Jake Gyllenhaal, who play Jeanette and Jerry Brinson, but the glue that holds it together is Ed Oxenbould, who plays their fourteen-year old son Joe. It’s 1960, and the family lives in a plain rental house in Great Falls, Montana, where Jerry has s job as a groundskeeper at the local golf club; Jeanette is a stay-at-home mom and Joe an awkward, lonely kid who’s joined the school football team at Jerry’s insistence but sits on the bench at practice.

Still, all seems to be going reasonably well until Jerry is abruptly fired while he and Joe are working on the club’s green, supposedly for being overly familiar with the customers. He takes his dismissal hard, dampening his anger over what he considers unfair treatment with increased intakes of beer; his search for a new job is desultory at best, and when his former employer asks him to return, he brusquely refuses, saying he’ll never work again for people who’ve treated him badly. Jeanette and Joe are concerned, of course, but Jerry’s dour, snappish responses to their questions create further rifts in the domestic situation.

Up to this point, there has been a consistent background hum about a wildfire raging some miles away, whose smoke is imperceptibly affecting the air in Great Falls. Now Jerry impulsively decides to join the local teams fighting it despite having no particular training. His absence leads to a major shift in Jeanette’s personality. She’d already begun looking for work, but now she takes up with a wealthy, and it turns out womanizing, widower, Warren Miller (Bill Camp), the owner of a car dealership whom she’s met on the one job she could find—giving swimming lessons. Before long they’re not-so-secretly involved, and she’s become highly extroverted—looking for a good time and drinking heavily herself.

We witness her transformation through Joe’s anxious eyes, both in an extended sequence when he and his mother join Miller for dinner at his home, and later when Warren spends the night at the Brinson house. Dano and cinematographer Diego Garcia stage these episodes in oblique terms, offering only imperfect glimpses of what’s going on behind half-closed doors as the boy strains to see, and achieving a sinister undercurrent in longer sequences, like the conversation Joe has with Warren while Jeanette has gone off to powder her nose at his place (Miller even offers him his first taste of wine).

Of course, when Jerry finally returns, he will find his wife much changed and unwilling to go back to her old life of circumspect subservience. He will discover that his son is different too, having given up football to become increasingly devoted to his part-time job with Clarence Snow (Darryl Cox), a local photographer who eventually puts him in charge of portraits. He’s also struck up a sort-of friendship with gregarious classmate Ruth-Ann (Zoe Margaret Colletti). In some respects he’s become more mature than his father, who reacts to the new domestic reality in an act that demonstrates juvenile recklessness. A coda incisively sketches the new family dynamic that results from the crisis the narrative has depicted.

Dano shows himself a skilled filmmaker in this directorial debut. He and his partner Zoe Kazan, with whom he collaborated on her charming romantic comedy “Ruby Sparks” (2012), have crafted a subtle, revealing script from Richard Ford’s 1990 novel, and his work with Garcia is precise and expressive, even though at times the images, with their steady focus and an inclination to place people and things on the edge of the frame, can seem a bit too artfully composed. An important element in the visual department is the careful deployment of period detail by production designer Akin McKenzie and costumer Amanda Ford; the mostly Oklahoma locations stand in effectively for Montana.

Dano also elicits superb performances from his cast, giving the film a strong dramatic pulse despite the measured pace of the editing of Matthew Hannam and Louise Ford. Gyllenhaal uses his ability to switch on a dime from apparent affability to simmering depression, his dark-shaded eyes glaring with rage, to best advantage, but it’s Mulligan who dominates, morphing from timorous housewife to unrestrained pleasure-seeker, and from doting mother to dismissive free spirit, in virtuoso fashion. Camp, too, offers an incisive portrait of a quietly libidinous older man.

The real centerpiece of the film, however, is Joe, and Oxenbould invests him with an aching vulnerability that conveys both the boy’s confusion about the forces swirling around him and his inability to control them. In its combination of fear, fortitude and resilience, it’s reminiscent to Dano’s own breakthrough performance in Michael Cuesta’s “L.I.E.” (2001), which is high praise indeed. Joe’s perspective is also that of the viewer, and if Oxenbould failed to hold our interest, neither would the film. Under Dano’s hand, he does.

With “Wildfire” one of the most remarkable of young American actors reveals a distinctive and compelling filmmaking voice. His initial feature is an exquisitely rendered chamber drama, a tale of domestic discord that’s probing, perceptive and intriguingly allusive.