For the record, I found “Grease: You’re the One That I Want,” the reality-TV program that used an “American Idol” format to cast the leads of the new Broadway revival, to be shabby even by the genre’s ignoble standards. The song selection was hideous, the camera crew captured the live performances with all the formal purity of blindfolded 8-year-olds swinging at a piñata, and the running commentary from “Grease” co-writer Jim Jacobs was equal parts fawning, lecherous, and tacky.

Also for the record, I only missed one episode of the entire run.

Now the winners of that show, Max Crumm and Laura Osnes, are taking the stage in Kathleen Marshall’s rickety revival of the unkillable 1972 musical. Shepherding this new talent — two fresh-faced 21-year-olds who edged out older, more Central Casting-friendly contenders — appears to have monopolized the time of director/choreographer Ms. Marshall, who also judged the television contest alongside Mr. Jacobs. Ms. Marshall’s revivals of musicals like “Two Gentlemen of Verona” and “The Pajama Game,” while light on dazzling innovations, have traditionally shown unassailable professionalism, bright period choreography, and a firm grip on pacing. And her latest project, with its romance between the gang leader Danny Zuko (Mr. Crumm) and the good girl Sandy Dumbrowski (Ms. Osnes) bracketed by harmlessly “naughty” 1950s nostalgia, boasts a bland but structurally sound script by Mr. Jacobs and Warren Casey that doesn’t need much in the way of coaxing.

But a few scenes in this “Grease,” including a half-baked “Beauty School Dropout” and an embarrassing cheerleading bit, are directed so indifferently that they might as well not even have been directed. And a mandate to replicate the smash 1978 film adaptation has saddled her with virtually unstageable material like the melodically and lyrically inappropriate title song that opens the new production. (“We take the pressure and we throw away / Conventionality belongs to yesterday”?)

The overall impression, then, is of a 10-year class reunion at a performing arts high school, one where the seasoned alumni strut their stuff in the solo scenes, then take breathers during the group numbers. And as a bonus, the top male and female seniors at the school get to join in — as the leads, no less. (Yes, the age difference between the TV contest winners and their costars is that stark.)

But not every supporting performer fades into the background. Lindsay Mendez gives a loose, infectious performance as the zaftig Jan, while Robyn Hurder’s voluptuous Marty incarnates a living, wriggling Vargas pinup. (Ms. Hurder is the most obvious beneficiary of Martin Pakledinaz’s clever costumes, which steer refreshingly clear of the standard-issue poodle skirts and Converse low-tops.) Matthew Saldivar, playing Kenickie as a dim bulb on the verge of sputtering out for good, finds several unexpected laughs. And the vocally impeccable Jenny Powers, previously a go-to good girl — she appeared in several ingenue roles at City Center’s Encores!, where Ms. Marshall spent four seasons as artistic director — struts away with each of her scenes as Rizzo, the reigning bad girl of the Pink Ladies.

Reigning, that is, until the finale, wherein Sandy finally earns the respect of her beloved Danny by pouring herself into skintight black leather and out-tramping Rizzo. Ms. Marshall tiptoes around the inherent squirm factor here by employing the strategy of having Sandy display mild unease with her new role as lust object. But after a squeamish grin and a few wobbles on her heels, Ms. Osnes offers all the cleavage and high kicks she can muster, while a delighted Mr. Crumm holds on for dear life.

Ah, yes, Max and Laura. Well, they sound much the same as they did when they sang the exact same songs umpteen times for the TV cameras; Ms. Osnes has a richer range, adorning her upper belt tones with an endearing girl-group shimmer, while Mr. Crumm does a better job at performing his songs, both the lyrics and the spaces in between. Mr. Crumm would be hard pressed to lead Spanky, Alfalfa, and the rest of “Our Gang,” let alone the T-Birds gang. “You’re the One That I Want” devoted virtually no airtime to acting ability, and here the onstage anxiety level appears to spike during their scenes of dialogue.

They are, we have been reminded ad nauseam, the ones that we wanted, and they are the ones that we got. (They are also, to be fair, no less ready for the big time than many of the C-list celebrities that were plunked into the even shoddier — and hugely popular — 1990s revival of “Grease.”) Welcome to Broadway, kids. Now take advantage of your strange and exciting opportunity. Pay close attention to the Matthew Saldivars and Jenny Powerses around you, and to the Fantasia Barrinos and David Hyde Pierces and Kerry Butlers nearby. The Broadway community is a welcoming one, and I genuinely believe it would be happy to have you back again soon, under more deserving circumstances.

Open run (256 W. 47th St., between Broadway and Eighth Avenue, 212-307-4100).