“Stars — They’re Just Like Us!” That’s the ingenious header Us Weekly gives a section of otherwise worthless paparazzi shots depicting incognito celebrities shopping for groceries, feeding the meter, and otherwise spotted doing activities far too banal to merit publication. Certainly, when the very same stars let the public into their lives, as they do via talk-show interviews or Instagram posts, they’re careful to curate what they share, largely sparing fans the bits that might undermine the fantasy of being famous.

And then there’s Shia LaBeouf, an incredibly gifted performer swept up by stardom who has pushed back on all the tabloid attention generated by his public intoxication, Ford truck-flipping accident, and so on. Since those incidents, LaBeouf has made it a point to demystify his celebrity, as when he attended the Berlin Film Festival wearing a paper bag over his head that read, “I Am Not Famous Anymore.” Oh, but he is still famous, and though he takes yet another swing at demolishing the wall that separates him from regular folks with “Honey Boy,” there’s no denying that the reason most people would consider watching this searingly personal, self-immolating childhood memoir — written by LaBeouf, directed by Alma Har’el, and unveiled at the Sundance Film Festival — is his famous-person status.

Ask yourself: Just how curious are you to understand the source of Shia LaBeouf’s insecurities and rage? If this is a subject of high importance to you, then you’re in luck, because “Honey Boy” offers a sincere window into the actor’s soul: a vulnerable, honest (or at least honest-seeming) act of therapy through screenwriting, in which LaBeouf explores his childhood relationship with his father, depicted here as a washed-up rodeo clown.

Although Har’el casts the best young actor of his generation, Lucas Hedges, as early-20s LaBeouf doppelgänger Otis Lort, and interweaves scenes of the star in therapy throughout the film, “Honey Boy” focuses primarily on the period in which 12-year-old Otis (“A Quiet Place” kiddo Noah Jupe) and his father, James (played by none other than LaBeouf), stayed in a sleazy motel — a far cry from Hollywood’s relatively posh Oakwood Apartments, where out-of-towner stage parents typically install themselves while shuttling their moppets from audition to audition.

That LaBeouf both wrote and stars in this film will surely interest his fans, as well as the haters frothing for a chance to eviscerate him at precisely the moment he’s being so open. Still, there’s something about the two-stage process that works to the film’s advantage: One senses that the very act of putting all this down on paper must have been purgative for LaBeouf, who seems to be vacillating between resentment and forgiveness toward his father. With those deep-buried grudges out in the open, the actor was then in a unique position to step into his father’s shoes and empathize with the man who had caused him such pain.

It’s an unusual opportunity for an actor, and one that allows LaBeouf to poke fun at certain elements — the ridiculous mullet, the tacky T-shirts, the tough-love parenting style — while also coming to terms with his father’s core humanity. The result is a tender portrayal of the man who damaged him, and a genuine attempt to break the cycle of alcoholism and abuse that reaches back generations — all of it visually heightened via Har’el’s collaboration with “The Neon Demon” cinematographer Natasha Braier and rendered emotionally resonant by a series of central performances that feel grounded, never gonzo.

Had LaBeouf also insisted on directing — the way Asia Argento did “Scarlet Diva” — he likely wouldn’t have found the distance he needed to disappear into the role and deliver one of his most multidimensional performances yet (the layers come through strongest in scenes without Otis, when LaBeouf is forced to conceive of his father as a person, not just the dad who done him wrong). And Har’el is a major talent who has demonstrated, via her 2011 documentary “Bombay Beach,” the poetic ability to look past surface judgments of struggling lower-class Americans and register what is universal about their experience.

That’s a surprising takeaway for a movie like “Honey Boy” at a moment when the culture of snark and ironic detachment doesn’t prepare us to identify with someone like LaBeouf. The distance between him and us appears all the greater at the outset, when Otis is introduced shooting a scene from what could be one of the “Transformers” movies. Har’el constructs her opening montage in such a way that neither audience nor Otis can seem to distinguish between the fantasy world of a movie set and real life.

At this early stage, they seem equally glamorous, as illustrated by a tryst with his co-star (Maika Monroe) back in his trailer, swiftly followed by a drunk-driving accident in which he flips the car with her in it and crushes his hand in the process — details that signify Otis is not intended to be read as a fictional construction, but at least semiautobiographical. It would have been nice to see more of Hedges, if only because LaBeouf’s off-screen personality is far more interesting these days than it was when he was 12, and yet, that seems to be the age when the trouble started (even if Jupe, while adorable, doesn’t show the potential of a youthful Shia).

We also meet young Otis dangling from a wire, taking a cream pie to the face on an “Even Stevens”-esque TV show. After the director calls “Cut,” the actor wanders back to find his father hitting on a PA, establishing a pattern of pathetic womanizing that seems entirely inappropriate for James, since he’s not only Otis’ dad but also his on-set guardian. Later, forced to confront his father (in a scene that feels like adult Shia talking, rather than something he would have been able to articulate at the time), a teary-eyed Otis hits him with, “You know I’m doing you a favor paying you to be my chaperone. Who else is going to give a felon a job?”

But long before allowing himself this catharsis, LaBeouf unloads his litany of grievances, clearing the bad-parenting closet of all its wire hangers, so to speak. There’s the drinking, the smoking, the slapping, the threats his dad made to his ex-wife’s new boyfriend (played here by Clifton Collins), the night he scared off a prostitute (FKA Twigs) who’d shown his son kindness, and the many instances when he undermined the boy’s fragile masculinity — even going so far as to belittle the boy’s underdeveloped genitalia. By including such details, LaBeouf is giving ammunition to his detractors, and yet, this film feels like an important step in his healing process (not that we need to be subjected to that).

In the framing scenes with Hedges, Laura San Giacomo plays a therapist/probation officer who recognizes Otis’ PTSD and pushes him to write down the most damaging memories as he unpacks them — which is clearly where this screenplay came from. It’s a sign of both LaBeouf’s bravery and his capacity for self-destruction that he should choose to share this journey with the public. While there’s no question that his upbringing was unique, a good deal of what he went through feels universal — or at least relatable — and sharing gives others a chance not only to understand him better as an artist but also to see themselves in his experience.

And yet, for all that may seem extreme and unfair about the way LaBeouf was raised, the movie unwisely tries to wrap things up with a neat bow, as if to suggest that all the writer needed to do was identify the source of this earlier trauma in order to make it right. The film isn’t so much a sign of maturity as an early step in that direction, and the decade of high-profile disturbia since the 2008 truck flipping has shown that the character Hedges portrays has a lot of self-analysis ahead of him.

But putting the mask that is Otis Lort aside for a moment to look at LaBeouf is also to recognize that something changed after that truck accident. Sure, he finished the Indiana Jones movie and made two more “Transformers” sequels, but he has also sought out serious roles with directors such as Andrea Arnold and Lars von Trier — and, of course, with Har’el, who takes full advantage of the actor’s commitment to creating meaningful work.

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