Jason Reitman Finds an Ideal Ensemble to Reenact the Lunacy from Which ‘SNL’ Was Born

Over nearly 1,000 episodes, “Saturday Night Live” has given America some of its most successful comedians, iconic characters and quotable catchphrases. Now, just one year shy of the pop phenom’s 50th anniversary, director Jason Reitman gives back, turning an oral history of the very first episode into a rowdy, delectably profane backstage homage. “Saturday Night” kicks off at 10 p.m. on Oct. 11, 1975, and ticks its way in practically real time to Chevy Chase’s delivery of the infamous opening line. Fine, but who plays Chevy Chase? Or Gilda Radner? Or John Belushi, for that matter?

The research is one thing, but Reitman — whose father, Ivan, directed his fair share of “SNL” legends, and who always dreamed of writing for the show — sets a foolhardy challenge for himself in finding sufficiently funny people to play some of TV’s most beloved cut-ups. Miraculously, Reitman and casting director John Papsidera pull it off, such that everyone reflects the singular energy (if not always the exact look) of their characters. You might not cast them in the biopic of any one individual, but as an ensemble, they’re terrific. That goes whether you’ve never seen an episode or can still remember arranging your Saturday nights around the show.

Ironically, the assignment calls for a different approach than the one taken by “SNL” itself. The show’s original ensemble was drawn primarily from Second City and National Lampoon, whose stars specialized in absurd characters and exaggerated impressions. Reitman required something subtler here — namely, actors who could channel the frailties and insecurities of their counterparts, taking icons and making them human.

Some of his cast aren’t even comedians by trade, such as Cory Michael Smith, the young Chevy Chase ringer, who’s acted mostly in Todd Haynes movies until now. I’d never before seen Matt Wood, who plays John Belushi, and certainly didn’t expect “Succession” cousin Nicholas Braun to appear in dual roles as Andy Kaufman and Jim Henson. (Yes, Henson did puppetry, for the grown-up “Land of Gorch” segments, throughout the first season.)

From the opening minutes of the film until seconds before showtime, producer Lorne Michaels (Gabriel LaBelle) is pressed to define “what is the show?” And no wonder: At 10 p.m., the infamous corkboard where the run of show is mapped out is overcrowded with “four host monologues, two standups, two musical guests each with two performances, a solo performance by Andy Kaufman, five parody commercials, Weekend Update, a film by Albert Brooks, Jim Henson’s Muppet thing, not to mention seven sketches.”

That’s easily three hours of material, which explains how Billy Crystal (Nicholas Podany) and many others wound up getting cut. But 90 minutes out, Michaels refuses to accept that he can’t somehow cram it all in. To skeptical boss Dick Ebersol (Cooper Hoffman), he insists, “You can’t expect them to recognize something they’ve never seen before.” To the all-powerful affiliates, he explains how “SNL” will be the first variety show made “by and for the generation that grew up on television.” And to NBC television exec David Tebet (Willem Dafoe), who’s ready to fall back on a rerun of “The Tonight Show Starring Johnny Carson” at a moment’s notice, he does his best to look confident amid the chaos.

Like the shambolic productions in so many backstage movies, it’s a wonder that “SNL” ever made it to air, judging by the disorder Reitman re-creates here — all true to (or at least inspired by) interviews with everyone alive at the time who’d share their memories of that historic night. A falling lighting rig nearly crushes Belushi and Radner (Ella Hunt) during rehearsal, one of the sets catches fire, drugs are ingested, egos are inflamed and no one can account for the llama roaming the halls (that gag is a nod to later seasons’ penchant for placing a random llama in backstage scenes).

Reitman isn’t the first to take audiences behind the scenes of “SNL” and its ilk — “30 Rock,” “Studio 60” and “The Larry Sanders Show” all demystified that world — but he does it so convincingly, “Saturday Night” seems destined to be the way many audiences remember the night that changed television: with Radner riding the camera crane like an MGM showgirl and sad-clown Belushi taking a quiet moment on the ice.

The logistical complexity of orchestrating so many moving parts seems every bit as daunting as, say, “Birdman” or “Babylon.” The difference is, Reitman isn’t showing off. If he stages an elaborate tracking shot through multiple sets, it’s because the material calls for it. Michaels and his fellow crew members — including Rosie Shuster (the great Rachel Sennott), to whom he is married, though she’s constantly flirting with Dan Aykroyd (Dylan O’Brien) — are never not multitasking. Pile all their stresses on top of one another, and there’s enough anxiety here to power New York City.

Looking for the right music to match that feeling, Reitman settled on Jon Batiste, who also plays musical guest Billy Preston. Batiste supplies a jumpy jazz score — full of clangs, bangs, rattles and drums — that’s both innovative (recorded live, like the show) and effective. By design, it sucks up every last molecule of air at times, going so far as to drown out important dialogue in the film’s Dolby Atmos sound mix. The instant Michaels steps into the control room (where Robert Wuhl mans the deck), the music stops and audiences can catch their breath … but not for long.

The crises keep on coming, but still Reitman makes time for each of the cast members. Jane Curtin (Kim Matula) rehearses a side-splitting steel wool commercial, Laraine Newman (Emily Fairn) practices her lightning costume-change skills and typecast Black multi-talent Garrett Morris (Lamorne Morris) gets a chance to sing. Morris spends most of the film questioning what he’s doing on such a project, Belushi waits until the very last minute to sign his contract and Chase gets his first taste of what the show will do for his career (in a scene with Tracy Letts that cuts-to-the-bone).

Described by Tebet as “a handsome funny Gentile” with sky’s-the-limit potential, Chase is cocky and combative with his co-stars, especially Belushi. But legendary comedian Milton Berle (J.K. Simmons) is cockier in the movie’s most memorable — and outrageous — cameo. Together, Berle and Carson represent the titans of TV comedy until that time. Carson held such power that he could make or break a young stand-up’s career simply by inviting the comic to sit on his couch. Then “SNL” came along, and suddenly, appearing on Michaels’ show made them stars (as it did for Steve Martin and such early cast members as Bill Murray and Eddie Murphy).

What then-30-year-old Michaels understood — and LaBelle captures, alongside a sense of near-crippling panic — was that younger audiences wanted something that spoke to them, even if meant testing the limits of NBC’s Standards department (represented here by Catherine Curtin, whose humorless censor lands the film’s biggest laughs). One of modern television’s most influential figures, Michaels possesses a clear vision, but also the wisdom to trust in talent, as when he steps aside to let Chase host Weekend Update. Not all his ideas work, as the Killer Bees (and most of the films he’s produced) would prove.

But that night was special. Reitman chronicles a turning point in television that reshaped America’s sense of humor — one that had been forecast by countercultural breakouts like Lenny Bruce, Cheech and Chong and the show’s first host, George Carlin (Matthew Rhys). It’s good that Reitman (who co-wrote with Gil Kenan) waited until now, after a decade-long cold streak in the “Juno” wunderkind’s career, to take on such a project. He’s tasted failure, and even though “SNL” went on to break every record, we have to believe it could flop for the film to work. Just look who gets the last laugh.