As pro boxing fades into oblivion, it threatens to take with it one of the great recurring characters in movies.

Palooka may be too harsh a term, but in various guises he’s the journeyman fighter, the washed-up champ, the veteran asked to take a dive.

On screen, there is something uniquely compelling about him, alone in the harsh glare of the ring, where the canvas-and-rope geometry diagrams stories of honor, defiance, compromise, age.

And what movies he has given us: “On the Waterfront,” “The Set-Up,” “Requiem for a Heavyweight,” and “Rocky.” The latter two are actually woven into the narrative of “Chuck,” the funny, poignant, and mostly true story of heavyweight fighter and living New Jersey legend Chuck Wepner.

It was Wepner’s 15-round feat of endurance, matched against Muhammad Ali in 1975, that gave Sylvester Stallone the germ of an idea that grew into “Rocky.”

Certainly, there is shared biography. Wepner grew up in a tough Rust Belt town (Bayonne), became a halfhearted leg-breaker (he didn’t like hurting people just because they were behind on payments), then a boxer who could throw a decent punch and — more important — weather a devastating blow.

Wepner became the heavyweight champ of New Jersey, ranked eighth in the world, often using his chin to make the other guy’s arms tired.

He earned the nickname “the Bayonne Bleeder” and once needed 70 stitches to close a cut opened up by Sonny Liston.

In “Chuck,” Wepner (Liev Schreiber) is an easygoing guy with a realistic assessment of his skills, and this gives him a rugged charm.

Wepner’s in on the joke when he watches “Requiem for a Heavyweight,” mouthing the lines along with punch-drunk, has-been champ Anthony Quinn. (Schreiber, so good as the hockey enforcer in “Goon,” has just the right read on Wepner, and the right physicality for the role.)

The movie is as genial and unsentimental as Wepner himself. When his manager (Ron Perlman) learns of promoter Don King’s plan to have Ali fight a disposable “white guy,” they are overjoyed to be chosen.

And the fight itself is amusingly presented — Wepner is as shocked as anyone when he knocks Ali down, and becomes suitably alarmed when the bored Ali, now ferociously roused, rises in his corner like a wounded lion.

Wepner hated being called “the Bayonne Bleeder” and liked being known as the “the Real Rocky,” but the parallels went only so far. Unlike Wepner, Rocky never went to jail for dealing cocaine.

But what’s a knockdown to a guy like Wepner? He does his two years behind bars the way he did his 15 rounds. He endures and survives.

“Chuck” is the funny, forgiving, eponymous movie he has earned, one that proves Palookaville is still one of the more interesting neighborhoods in cinema.