In the immortal words of the then-recently fired “Saturday Night Live” star Norm MacDonald, “the show has gotten really bad!” But “SNL” didn’t always used to be so unfunny and politically unhinged. A new film from director Jason Reitman tells the 1970s origin story of this once-great institution of comedy.

Reitman is known for his critically acclaimed successes with “Juno,” “Thank You for Smoking,” and “Up in the Air” which set him apart as one of the great directors of his generation, being a director who could handle comedy and drama with equal skill. While his later films like “Tully,” “Labor Day,” and “The Front Runner” lost some of that momentum, his work as the director of “Ghostbusters: Afterlife” and screenwriter of “Ghostbusters: Frozen Empire” has kept him in Hollywood’s good graces (in addition to being the son of Hollywood legend Ivan Reitman).

Even when his films flounder, they still have the unique humanist and libertarian voice of his early works. Thankfully, his recent financial successes have allowed him to direct one of his best films in ages. And while that film, unfortunately, bombed at the box office — grossing $8 million on a $30 million budget — ”Saturday Night” shines as both a great work of comedy and a stressful work of drama that captures the immortal challenges of art from adversity. 

Lorne Michaels holds the rare distinction of being one of the most influential visionaries in comedy history, having the vision to turn a rag-tag group of Chicago Second City standups and small-time Canadian comedians into one of the most successful comedy institutions of the past 50 years. However, his was a jilted vision with an unclear recipe and volatile ingredients. The writer’s room of “Saturday Night Live” is infamously one of the hottest seats in Hollywood, a hotbed of hotheads and egos that makes and breaks careers before they start.  

“Saturday Night” captures this volatility with surprising panache, captured in real-time “Goodfellas”-esque long-shots and interweaving biographical sketches that jump between the dozens of personalities, techies, and junkies roaming behind the scenes at NBC’s New York City studio. 

Set against the 90 minutes leading up to the series premiere on Oct. 11, 1975, “Saturday Night” is told in real-time. Michaels is stuck with the unenviable task of herding the chaotic, egomaniacal, and uncooperative cast like cats through a last-minute dress rehearsal where the scripts aren’t ready, the AV equipment is breaking down, and the studio is nipping at their heels. The bricks on the stage aren’t even cemented in place. 

The biggest question the film returns to throughout is what this enterprise is supposed to be. Michaels is frequently cornered by studio executive David Tebet (Willem Dafoe), who sees the young producer as both a daring genius and a disorganized amateur who isn’t ready for primetime, eager to pull the plug on the show and rerun an episode of “The Tonight Show” with less than a second’s notice. 

And Tebet has good reason not to trust Michaels. The actors are antagonizing each other, the set is catching on fire, the writers are smoking pot, the three-hour set is twice as long as the network permits, and Johnny Carson is angling to push them off the air. John Belushi (Matt Wood) in particular is unwilling to even sign his contract and Chevy Chase (Cory Michael Smith) is feuding with costars and old studio legends like Milton Berle (J. K. Simmons).  

Thankfully, Michael’s vision is potent, if unclear. He’s pulled together a larger group of disagreeable loudmouths, political radicals, potheads, and irreverent nihilists to capture something authentic and new — a new kind of comedy show that’s rawer and more radical kind of television show. It’s a comedy troupe that sits around antagonizing the overbearing evangelical NBC censor with all the writers yelling “I am Satan” in the manner of “I am Spartacus.”

The politics of “Saturday Night Live” thus becomes the politics of irreverence and transgression, the popularization of the Baby Boomer generation’s comedic ideals. As Michaels puts it, he wants to create a comedy show that captures the chaotic feel of life in New York City, even if he has to pull in random comedians off the street to make that happen. 

“Saturday Night” is a wonderful celebration of that cultural moment, and pulls together a wonderfully cathartic story in honor of that chaotic lot. While there’s a fair amount of commentary about its strict historical inaccuracies, it maintains the essence of what that moment meant. 

The real “Saturday Night Live” has squandered its cultural relevance, producing less than a handful of memorable sketches in recent years, cut between aggressively unfunny bits like Kate McKinnon’s “Hallelujah” performance after the 2016 election (Nate Bargatze’s “Washington’s Dream” and Tom Hanks’ “Black Jeopardy” come to mind as rare bright spots). This movie’s only shame is that it mythologizes the comedy titan and cultural institution that has been on the downslope for more than a decade now.