For most of “The Florida Project,” I found myself rooting for unseen authorities.

The police. The Florida Department of Children and Families. Maybe a church leader.

Someone to swoop in and rescue a little girl from her monstrously unfit mother and to provide much-needed psychological help for this child, who already has picked up some alarmingly anti-social tendencies (and that might be understating it) from her mom.

With “The Florida Project,” the gifted writer-director Sean Baker delivers a sun-dappled but decidedly dark and severely fractured (and occasionally class-condescending) fairy tale, set so close to Disney World you can see the fireworks popping off in the distance at night — but a galaxy away for the impoverished children who live in the garishly painted, barely inhabitable, rundown motels of certain Orlando suburbs.

Often shot from the point of view of the young children who roam the properties and nearby streets with either no adult supervision, or “supervision” so incompetent they might be better off on their own, “The Florida Project” does a masterful job of exploring a world rarely explored in movies: the almost completely dream-free lives of poverty-class millennials (many of them parents) who barely get by on part-time, hourly wage jobs and/or misdemeanor-level moneymaking schemes.

They work as maids in the nicer hotels, or patrol the parking lots of those hotels, trying to resell cheap perfume to guilty rich folks at a steep markup. They’re cashiers in tacky souvenir shops or reduced-price ticket kiosks. They scrap and scrape to make enough for their $35 a night “rent” payment. (At the end of each month, they have to put their things in storage, move out of their rooms and stay at a nearby motel for a night, because they’re not allowed to establish permanent residency in any of these places.)

They live with their kids in tiny motel rooms, with the TV or music almost always blaring, and junk food strewn about. If they spend any time trying to teach their children to learn, we don’t see it in this movie. (Hence my earlier comment about class condescension.)

In a remarkable performance free of self-conscious, child-actor mannerisms, Brooklynn Prince plays Moonee, a girl of about 6 who is bright and filled with energy and sometimes adorable and cheerful — but also manipulative and dishonest and a little mean-spirited and temperamental.

Moonee and her little running mates Scooty (Christopher Rivera) and Jancey (Valeria Cotto) get themselves into all sorts of trouble, ranging from the disturbing but relatively harmless to the disturbing and potentially quite harmful.

Moonee is the leader of the bunch, giving the lay of the land to new arrival Jancey. She says not to use the elevator because it always smells of urine. She’s the tour guide to food stands where if they hang around long enough, the proprietors will give them free treats just so they’ll go away. She’s a resourceful kid and even when she’s getting into trouble, she breaks your heart because even though she’s awfully cynical for someone her age, she’s not sophisticated enough to realize every street in her neighborhood might as well be a dead end.

Bria Vinaite is so good as Halley, Moonee’s nightmare of a mother, we want to yell at the screen for her to get her stuff together. Halley loves Moonee, but she can’t take care of herself, let alone a child. She can’t hold a job, she has a horrible temper, she’s had multiple run-ins with the law — and when there’s no money left, she advertises herself online and welcomes a steady parade of men into the tiny motel room, parking Moonee in the bathroom and turning up the radio so Moonee can’t hear what’s happening on the other side of the door.

In one of the finest performances of a long and varied career, Willem Dafoe is Bobby, the manager of the motel.

Talk about a thankless job. Not a day goes by — heck, not an HOUR goes by — without some problem, whether it’s a guest behind on her rent slamming the door in his face, or busted washing machines in the laundry room, or a creepy adult stranger wandering over and talking to kids in the rusted-out playground, or a 70ish female guest insisting on going topless at the swimming pool, which looks like the sort of swimming pool in which no one should ever go swimming.

Bobby’s kind of a hapless character — apologetic to a fault, intimidated by some of the guests — but he’s pretty damn heroic in his own way, in this small and godforsaken corner of the world. Even as the kids are driving him nuts and giving him lip and screaming things like, “You’re not my father!,” you get the impression they realize on some level he’s the closest thing to a positive adult role model in their lives.

As “The Florida Project” grows bleaker, writer-director Baker nimbly shifts the tone of the film, with the skies literally growing darker, and certain characters meeting the consequences of their actions. It’s film that’ll make you wince at times, and you’ll most likely not want to see twice, but seeing it once is an experience you’ll not soon forget.

★★★1⁄2

A24 presents a film directed by Sean Baker and written by Baker and Chris Bergoch. Rated R (for language throughout, disturbing behavior, sexual references and some drug material). Running time: 115 minutes. Opens Friday at local theaters.