During the first act of A Complete Unknown, the splashy new biopic about Bob Dylan, the songwriter gets into a fight with his girlfriend, Sylvie Russo, a character based on the real-life Suze Rotolo. Sylvie (Elle Fanning) is frustrated that her evasive new beau (Timothée Chalamet) keeps his backstory a secret.

“You never talk about your family, your past!” Sylvie protests, calling him “a mysterious minstrel.” Dylan retorts, “People make up their past, Sylvie! They remember what they want, they forget the rest.”

Sylvie’s critique reverberated through my head as A Complete Unknown marched towards its preordained climax, ticking off a grab-bag of nostalgic Boomer pleasure centers along the way. Despite the impressive efforts of Chalamet, filmmaker James Mangold, screenwriter Jay Cocks, and a fine supporting cast, Dylan remains an enigma, as unknowable to the audience as he is to his lover.

It’s all there in the title, with its myriad meanings — a playful wink to “Like a Rolling Stone,” a reference to the songwriter’s roots as a folkie nobody from Minnesota, but also, perhaps, a commentary on this icon’s fundamental unknowability. Complete unknown, indeed.

How do you make a movie about a guy who’s a tangle of contradictions, more myth than man? In 2007, Todd Haynes answered this question with I’m Not There, a kind of biopic as collage, as fragmented as the man himself. That film was easier to admire than love for its subversion of biopic tropes, and it bombed at the box office. Its overarching message — you can’t make a normal biopic about this guy! — proved incompatible with the Normal Biopic Industrial Complex.

Inevitably, Hollywood decided Dylan was ripe for a more conventional treatment, and they found the guy for the job in Mangold, who, two decades ago, helped inaugurate Hollywood’s unending glut of music biopics with Walk the Line, a deserved classic of the genre.

Wisely, A Complete Unknown resists the sprawling career-spanning arc — Chalamet is hardly primed to play ’80s born-again Dylan — and zooms in on a pivotal period from 1961, when a teenage Dylan first arrived in New York, to 1965, when he shocked the folk establishment by going electric.

During the opening sequence, the young folkie hitchhikes to New Jersey to visit his ailing idol, Woody Guthrie (Scoot McNairy). There, he befriends folksinger/activist Pete Seeger (Edward Norton), who takes the young talent under his wing, becoming a mentor as Dylan navigates the Greenwich Village folk scene.

If anyone deserves Oscar buzz here, it’s Norton, who embodies Seeger with a kind of paternal, benevolent gravity that curdles into stodgy traditionalism during the third act, as Dylan breaks with the establishment. If the character’s involvement in Dylan’s early career is overstated a bit, it instills the film with a compelling changing-of-the-guard arc.

Dylan makes a name for himself performing at downtown clubs like the Gaslight, where he catches the attention of both Joan Baez (Monica Barbaro), who becomes his collaborator and tumultuous lover, and Albert Grossman (Dan Fogler), his tough-minded manager. Fame comes quickly, earning him the right to record his original tunes but compromising his privacy, and we get the obligatory sequences of Dylan mobbed by female fans in a cab outside his apartment and squabbling with Baez onstage during a fraught tour.

Mangold is a skilled, inventive director, and he captures the ’60s milieu with stunning visual flourishes. A vibe shift arrives as 1964 turns into 1965; a sense of revolution suffuses the air, and there’s a remarkable sequence of Dylan, shades on, roaming the Village, nabbing a siren whistle (as heard in “Highway 61 Revisited”) from a streetseller, and then speeding away on his motorcycle, as throbbing jazz cacophony fills the air.

Mangold frequently frames the singer at a remove from his contemporaries — a long shot of Dylan onstage at Newport with Baez emphasizes a microphone between their faces, symbolizing the vast gulf separating them.

Chalamet performs a plethora of Dylan tunes throughout the film — he spent years training with dialect and harmonica coaches, and his vocals are all done live, apparently, with vintage microphones and solid simulacrums of Dylan’s wheezy voice.

As in Walk the Line, Mangold has a knack for staging mini psychosexual dramas within the the songs themselves. As Dylan sounds out “Blowin’ in the Wind” in Baez’s apartment, for instance, her irritation with this arrogant wunderkind melts, and she impulsively starts singing along on harmony.

And yet, A Complete Unknown can’t quite figure out who Dylan was or what made him tick. Where did those songs come from? A sequence of the man viewing newsreel footage of the Cuban Missile Crisis, then writing “Masters of War” offers a facile narrative.

Chalamet delivers disaffected Dylanisms like “They should just shut the fuck up and let me be” in a distractingly nasal-pinched imitation of Dylan’s voice. He is never wholly convincing as Dylan. He looks too much like, well, Timothée Chalamet — too pretty, too delicate — and plays the character as a set of surly, brooding glances that fail to capture Dylan’s mischievous humor. The film suggests that Dylan’s essence lies in his defiant, iconoclastic attitude, but Mangold — a committed crowd-pleaser — can’t quite match that energy as a director.

As A Complete Unknown culminates in a remarkable recreation of Dylan’s electric set at the 1965 Newport Folk Festival, it’s hard for Mangold to resist glaring factual errors (an audience member shouts “Judas,” which actually occurred in England) or escape Walk the Line‘s shadow.

There are playful callbacks (in the 2005 film, Johnny Cash writes to a young folksinger named Bob Dylan; here, we see Dylan receiving Cash’s letter) and structural parallels. Both films depict the hero navigating a love triangle between a woman he lives with (Sylvie) and a more worldly woman with whom he performs (Baez), and both climax with a heady recreation of an iconic 1960s performance instilled with anti-establishment significance. (Cash even emerges as a supporting player during A Complete Unknown‘s third act, encouraging Dylan to break all the rules.)

And yet Chalamet lacks the presence and suspension of disbelief that Joaquin Phoenix summoned as Cash in Walk the Line. Chalamet is a generational talent in his own right, but here he looks like a model dressed in a Dylan Halloween costume. It’s a good Halloween costume — the kind that turns heads at parties and gets a lot of Instagram likes. But no one’s going to confuse it for the real thing.

A Complete Unknown (★★★☆☆) opens nationwide on Wednesday, Dec. 25. Visit www.fandango.com.