“The Comedian”

**1/2

(R, 1:59)

Is Robert De Niro back? Can it be true? It seemed for a long while there that we had lost the beloved tough-guy actor forever to demeaning projects like “Dirty Grandpa” and blink-and-you’ll-miss-it boxing movies, but Taylor Hackford’s “The Comedian” shows promise for De Niro fans. It’s a truly lived-in, committed and sincere performance, playing an aging comic, Jackie Burke, who can’t manage to outpace his past starring as Eddie in the ’80s sitcom “Eddie’s Home.”

But Jackie just wants to be Jackie, not Eddie anymore. When a heckler taunts him into a confrontation at a gig, a video of the scuffle goes viral, and Jackie is sent to the clink for 30 days and tasked with community service. Somehow that manages to be the turn upward for his career — and his life. Part of being Jackie — not Eddie — is freedom from the family-friendly sitcom leash, and he takes every opportunity to test those boundaries, plunging instantly into aggressive crowd work and ribald blue humor, whether he’s at a gig or not.

De Niro sells both the stand-up and the well-rounded performance of a man who’s always on but searching for a deeper connection, whether he’d admit that or not. His relationships range from the strained (with his brother and sister-in-law, played by Danny DeVito and Patti LuPone) to the combative (with his manager Miller, played by Edie Falco) to the casual, friendly ribbing with the comics at the Comedy Cellar. So meeting Harmony (Leslie Mann) at the homeless shelter, where they’re both working off their court-mandated community service hours, offers the opportunity for something else.

The world of “The Comedian” feels authentic, with De Niro surrounded by real comedians and old compatriots alike. One can’t deny the thrill of watching De Niro and Harvey Keitel — who plays Harmony’s reformed gangster father, Mac — face off one more time. Scenes in the Friars Club are a treat, especially some testy back-and-forth with Charles Grodin, and a roast featuring Cloris Leachman is the pinnacle of the film’s humor.

“The Comedian” builds a lilting rhythm around each time Jackie gets called to perform — at a small birthday dinner, at a wedding, heckled from the stage, visiting a retirement home, signing autographs, apologizing in court. Jackie always complies when asked — but he can’t resist his own worst instincts, compulsively descending into the crudest, most offensive material possible. But somehow he manages to yank everyone back up with a self-deprecating show of his own vulnerability, a reminder that we’re all in this together and that sometimes poop is funny.

Harmony shares a sensibility with Jackie, and Mann is compelling in her delicately wrought if familiarly frantic performance. She’s the character in whom Jackie finds something to care about. But the arc of her character shows that the filmmakers didn’t know what to do with a complex woman like Harmony, despite her potential. She’s wacky, funny, angry and just as off-kilter as he is, but she’s quickly set aside for Jackie’s journey to continue, and their combustible chemistry is squandered for stale plot developments that drag the whole thing down. The world of the “The Comedian” is rich, the themes often thought-provoking. But it eschews all that for a cutesy happy ending, one that Jackie definitely wouldn’t approve of.