Monica Barbaro plays Joan Baez to Chalamet’s Dylan in “A Complete Unknown.” Searchlight Pictures

If you’re over 60, chances are you’ve spent at least a few chapters of your life tangled up in Bob. If you’re under 30, Dylan is that musician who sings like a goat that your cool aunt likes. A life story of the man born Robert Zimmerman has got to serve somebody, but who? Choices must be made, timelines compressed, facts weighed against the legend. Not everybody must get stoned.

Adapting Elijah Wald’s fine 2015 history “Dylan Goes Electric! Newport, Seeger, Dylan, and the Night That Split the Sixties,” “A Complete Unknown” opts for the legend, and ably enough for newcomers and folks who were never quite sure what all the fuss was about. Directed by James Mangold (“Walk the Line”), it’s a brisk, tuneful and very entertaining two hours and 20 minutes of bog-standard Hollywood biopic, with a popular and talented boychick in the lead to bring in Generation Z.

So how is the boychick? He’s excellent, even if he gives the second-best performance in the movie. The story is that Timothée Chalamet had been preparing to play the young Bob Dylan for five years, learning the guitar and harmonica and working hard to nail that singular moon-cow voice. The technical effort has paid off, but, more important, Chalamet conveys the presence of this upstart kid folkie – the certainty and sullenness, the ear that’s listening more to the siren songs in his head than to anyone in the room. The work ethic and the contempt, the restlessness and the masks, the burning lyrics and the voice of an ornery young prophet – it’s all there except for the lightness, the prankishness that Dylan possessed in his early years, before everyone mistook him for God. Chalamet’s Dylan is heavy with coming greatness.

Covering the first four rocket-fueled years of Dylan’s career, from his 1961 arrival in Greenwich Village as a 19-year-old Minnesota nobody to his betrayal of the folk revival by plugging in at Newport ’65, “A Complete Unknown” places the singer at the center of a young, earnest and fed-up counterculture. The music is seen as a connection to an older, more oppressed version of America: It’s a music of protest against nuclear proliferation and in support of civil rights, and at first Dylan fits right in.

The script by Mangold and Jay Cocks has Bob turning up at the New Jersey hospital bedside of Woody Guthrie (played by Scoot McNairy), who’s dying of Huntington’s disease. Pete Seeger (Edward Norton) is there, too, and the kid sings the older men a song – “Song for Woody” – that so touches Seeger that he brings Dylan home to his wife, Toshi (Eriko Hatsune), and family to spend the night. It didn’t happen this way, but it’s nice to think it could have.

Chalamet is said to have spent five years preparing to play Dylan. Macall Polay/Searchlight Pictures

Dylan’s months of apprenticeship on the Village coffeehouse scene, honing his persona and his chops, are elided into one Village cafe appearance at which four people important to the story are conveniently present: Robert Shelton, the New York Times writer whose September 1961 story on Dylan boosted the singer’s career; the powerful record producer John Hammond (David Alan Basche); a gleefully rotund shark named Albert Goldman (Dan Fogler), who’ll become Dylan’s manager; and Joan Baez (Monica Barbaro), who’ll become his lover and rival.

“A Complete Unknown” puts across two important ideas: That the folk revival was a staid and rather privileged reworking of older material and that Dylan blew everything up by writing his own songs. And what songs! The movie conveys the electrifying impact that “Blowin’ in the Wind” and “Masters of War” had on their first audiences; by the time Dylan introduces “The Times They Are a-Changin’” at Newport ’64, the crowd has adopted it as an anthem before he even gets to the second verse. (Which also didn’t happen, by the way.)

To a lot of people, Dylan was a savior; to the folk scene’s old guard, he was increasingly a threat. “A Complete Unknown” accurately reflects the awe in which the young Dylan was held by people like Seeger and Alan Lomax (Norbert Leo Butz), the storied field recordist and pillar of the Newport Folk Festival. And it accurately dramatizes their concern as the young Jeremiah in their midst defiantly went his own way.

“What do you want to be?” asks Bobby Neuwirth (Will Harrison), one of the few in Dylan’s circle who treated him simply as a friend. “Whatever it is they don’t want me to be,” Dylan snaps. Like his idol Marlon Brando, he rejected fame, and in that rejection seemed more glamorous, more necessary than ever. (How obsessively did people try to “solve” Bob Dylan? There was a man who became well-known for going through the singer’s garbage, looking for clues.)

Confronted with mobs chasing their new guru across the street demanding the Truth, Chalamet’s Dylan retreats behind sunglasses, a sneer and rock-and-roll, which to middle-class folkies was the music of greasers and thugs. He shows up in the recording studio with a crew of bad boys, including guitarist Mike Bloomfield (Eli Brown) and Al Kooper (Charlie Tahan), who sits in on organ for “Like a Rolling Stone” because the producers have expressly told him not to. (Imagine that song without Kooper – you can’t.) The music is raw, electric – the real Dylan called it “a thin, wild, mercury sound” – and supremely pissed off. About everything: fame and women, all the uncomprehending Mr. Joneses out there.

Edward Norton gives a terrific performance as folk singer Pete Seeger. Searchlight Pictures

In this movie, the chief Mr. Jones – all that Bob is pushing against, whether he knows it or not – is Pete Seeger. A pitch-perfect Norton turns that betrayal into the most unexpectedly tragic aspect of “A Complete Unknown.” Seeger – sweet, sanctimonious, unironic Pete – was indispensable to bringing folk music and its socially progressive conscience to the young boomer masses. In Norton’s performance, you see the sorrow creep into the older man’s eyes as Dylan abandons his gift for what Seeger can’t understand is a greater one – the fusing of folk and rock, pop and poetry, mass connection, and a far more profound sense of revolt. I enjoyed Chalamet’s performance, but Norton’s made me giddy, so perfectly does he capture Pete’s generosity, piousness and near-total incomprehension at what’s happening – his entire generation made passé, overnight.

What’s missing from “A Complete Unknown”? The drugs, for one – amphetamines, specifically – and a deeper immersion in the folk scene. I would have liked more than two brief appearances of Joe Tippett as folk singer Dave Van Ronk, and let’s just say that a movie about a man who wrote more (and better) kiss-off tunes than love songs isn’t going to give a lot of space to the women in his story. Suze Rotolo, the girlfriend clinging to Dylan on the cover of his breakthrough second album, “The Freewheelin’ Bob Dylan,” has been fictionalized (apparently at the singer’s request) as Sylvie Russo (Elle Fanning); she and Barbaro’s more tough-nosed Baez fight a losing battle for the singer’s and the movie’s attention.

More glaringly, the climax at the 1965 Newport Folk Festival plays up the legend and then some, as the crowd of folkies responds to the sonic blast of “Maggie’s Farm” with boos and near rioting. Does it matter that a large part of the problem was an acoustic festival’s sound system that wasn’t up to the challenge and that reduced Dylan’s rock revolution to sonic mud? Or that an audience member yelling “Judas!” wouldn’t actually happen for another year and in another country?

Probably not for most moviegoers, but truth in the face of commercialism used to matter to the young Dylan, and I wonder what the old one thinks about that now. On the other hand, he always did like to tell tall tales about himself. Maybe this is just the latest, as far as he’s concerned.

The irony is that the great Bob Dylan biopic already exists: Todd Haynes’s “I’m Not There” from 2007, a movie as challenging as any Dylan song and one that responds to his career-long trickery by casting six actors to play him, including Cate Blanchett and a young Black boy.

That film, Wald’s book and Martin Scorsese’s 2005 “No Direction Home” documentary are all you need if you want to know the facts and the bones, the jewels and binoculars, of Dylan’s ascension. “A Complete Unknown” just tells the story. But maybe that’s enough for a fresh generation to feel the joy of his apostasy at a moment when the world seems once more poised on a precipice of chicanery, treachery and disaster. If so, well, how does it feel?

R. In area theaters. Language. 140 minutes.

Ty Burr is the author of the movie recommendation newsletter Ty Burr’s Watch List at www.tyburrswatchlist.com.