I met John Lloyd Young at the 2004 William Inge Theatre Festival. We became friends immediately and he’s given me great feedback on my play. Last spring he told me that he was up for a part in the new musical “Jersey Boys” that was going to go to Broadway. It’s the story of Frankie Valli and the Four Seasons, and John was up for the lead. He got it, and last night it opened at the August Wilson Theatre on Broadway. Here in its entirety — with emphasis added — is Ben Brantley’s review from the New York Times.

A rush of vertigo, pleasurable but a little scary, descends around the middle of the second act of “Jersey Boys,” the shrink-wrapped musical biography of the pop group the Four Seasons, which opened last night at the August Wilson Theater. This dizziness arrives during the kind of big showbiz moment (category: The Comeback) that anyone familiar with backstage back stories knows all too well.

Our superstar hero – in this case, the singer Frankie Valli, played by a genuine star-in-the-making named John Lloyd Young – has already scrambled from the mean streets of his youth to the heights of Top-40 glory and started the long, scraping slide downward. But there’s this one song, see, that he knows can push him back into the big time, and no one will play it on the radio. So he takes his song straight to the people, and by golly, when he’s finished performing it, the crowd goes wild. I’m talking about the real, mostly middle-aged crowd at the August Wilson Theater, who seem to have forgotten what year it is or how old they are or, most important, that John Lloyd Young is not Frankie Valli.

That song, by the way, is “Can’t Take My Eyes Off of You,” an after-shave-soaked lounge ballad that was a hit in 1967 and is not a personal favorite of mine. But that’s not the point. Nor is the point that Mr. Young – who has been doing a swell imitation of Mr. Valli’s trademark nasal crooning throughout this “Behind the Music”-style concoction, directed with more efficiency than originality by Des McAnuff – has again delivered a spot-on evocation of a voice that continues to dominate golden oldie stations.

No, the real thrill, at least for those who want something more than recycled chart toppers and a story line poured from a can, is that Mr. Young has crossed the line from exact impersonation into something more compelling. It’s that sort of melting from perfect wax effigy into imperfect flesh that Philip Seymour Hoffman achieves in the title role of the current movie “Capote.”

Inhaling the cheers of the crowd, Mr. Young as Mr. Valli glistens with that mix of tears and sweat, of humility and omnipotence, that signal that a hungry performer’s need for approval has been more than met. And everything that has led up to that curtain call feels, for just a second, as real and vivid as the sting of your hands clapping together.

It would be, to borrow a phrase from the aforementioned song, just too good to be true that the rest of “Jersey Boys” should achieve this level of conviction. Shaped by the scriptwriters Marshall Brickman and Rick Elice as a cross between “Dreamgirls” (the Motown heartbreak-of-success musical) and Martin Scorsese’s “Goodfellas” (the Mafia kneecap-break-of-success movie), the plot follows a much-traveled stretch of highway with few illuminating detours.

But in a year in which one pop-songbook show after another has thudded and died, “Jersey Boys” passes as silver instead of as the chrome-plated jukebox that it is. Unlike the recent Broadway flops “Good Vibrations” (the Beach Boys show), “All Shook Up” (the Elvis show) and “Lennon” (you figure it out), “Jersey Boys” has the advantage of featuring singers that actually sound like the singers they are portraying and a technology-enhanced band that approximates the original sound of their music.

The show’s straightforward biographical approach is a relief after the hagiography of “Lennon” and the clunky fantasy story lines, inspired by the perversely inimitable “Mamma Mia!” (the Abba show), of “Good Vibrations” and “All Shook Up.” Mr. Brickman (who collaborated with Woody Allen on the screenplays for “Annie Hall” and “Manhattan”) and Mr. Elice provide some likably sassy dialogue as they chart the evolution of their main characters from street kids in the urban wastelands of New Jersey to pop gods enshrined in the Rock and Roll Hall of Fame.

Mr. McAnuff, who won a Tony for repackaging rock for Broadway in “The Who’s Tommy” in 1993, lends clarity and crispness to a shifting narrative that lets the different Seasons tell their own sides of their story. They are, in addition to Mr. Valli, Tommy DeVito (Christian Hoff), the group’s bad-boy organizer; Bob Gaudio (Daniel Reichard), the genius songwriter; and Nick Massi (J. Robert Spencer), the self-described Ringo (as in Starr) of the bunch. If none of these actors matches the white-hot sincerity of Mr. Young, they are all appealing. And no one overdoes his allotted shtick.

But while “Jersey Boys” is based on fact, it rarely leaps over the clichés of a regulation grit-to-glamour blueprint. (There is at least a clever, expectation-thwarting opening scene, with the Seasons standard “December, 1963 (Oh, What a Night)” sung by a funky French pop group.) Only in the second act, when the group is breaking up, does the show integrate the songs in a way that excitingly enhances and furthers the plot. And the Roy Lichtenstein-style projections (by Michael Clark) that signal time and scene changes in Klara Zieglerova’s standard-issue industrial set feel inappropriately arch.

But ultimately what’s demanded by the baby-boomer theatergoers that “Jersey Boys” seems destined to attract is a mimetically precise rendering of songs like “Big Girls Don’t Cry,” “Rag Doll” and “Walk Like a Man,” composed by Mr. Gaudio with lyrics by Bob Crewe (portrayed here as a gay diva of a record producer by Peter Gregus). Because the show uses mood-setting standards by other artists in its first quarter, you can feel the audience getting restless, waiting for “the real thing.”

But once the Four Seasons classics are rolled out, every other pair of shoulders in the house starts a-twitchin’. With their three-part-harmony behind Mr. Valli’s hearty falsetto, the group’s songs remain exasperatingly infectious. And as choreographed by Sergio Trujillo, Messrs. Young, Hoff, Reichard and Spencer come as close to simulating the originals as any pop impersonators on Broadway since “Beatlemania.”

The chief source of fresh air, though, is Mr. Young, who mutates from hopeful teenaged schlemiel to regretful falling idol with a spontaneity that never fades. When this Frankie Valli sings, you sense him channeling all the messy, happy, angry feelings of his life without straying from the required official voice. Like Mr. Valli, Mr. Young has a quirky authenticity that can’t be faked or learned. His intense belief in his character shimmers like sunlight amid the fluorescence of “Jersey Boys.”

It is a huge thrill to see someone like John Lloyd Young make the breakthrough that so many actors just dream of. Congratulations, JLY — it couldn’t have happened to a nicer guy.

Here’s a profile of JLY that appeared in the New York Times on Sunday.

PS: John’s blog has been on the blogroll since last year; stop by and drop him a note.