A couple of things you might guess about a redeemed-by-faith story co-starring Mark Wahlberg and Mel Gibson.

It’s going to have edge, because Wahlberg’s voice is best-suited for swearing. And it’ll be Catholic, because Gibson’s love-hate affair with what was once his mother church is as well-documented as his other personal struggles.

You can’t say “Father Stu” isn’t that unicorn of faith-based film, a movie that sounds and feels like a slice of real life. People — especially Wahlberg in the title role — curse like the disgraced former president and drink like…Mel Gibson. This goes on, first scene to last.

There’s blue collar poverty, frustration and impulse control. Violence takes many forms — lashing-out fistfights, “boxing as a way out” and drunk driving accidents. Sex is a goal, love almost a byproduct.

Yes, this R-rated drama feels real and lived-in. And Wahlberg goes all-in bringing this mug who found faith to life. If only that was enough.

Stuart Long is a Fu Manchu’d boxer when we meet him, a Montanan getting the straight dope from his doctor that “Your body is telling you not to fight.” His mother (Jacki Weaver) is glad to hear it, but Mr. “No regular job for me” isn’t having it. Then he is.

He was “all-in” on the boxing thing, seen in a long opening montage of fights. He now decides the time is right to go to Hollywood, “cash in my face instead of my fists.” He doesn’t require much money to travel.

“I don’t need a month to ‘make it!'” And he doesn’t need to get in touch with his estranged Dad (Gibson) already out there among the “communist…fascist hippies,” an alcoholic construction worker who — like Stu and his mom — never got over the death of Stu’s kid brother at five.

That may be the most heartfelt element of “Father Stu,” its depiction of a wound that never heals. Whatever dreams of singing fame Stu harbored as a kid, boxing became more his speed — an outlet for violence. However much his Dad enjoyed his PBR back in the day, it and whisky morphed into his medication afterwards. And the entire family’s rank contempt of religion was born when that kid died.

In LA, Stu gets a job at the meat counter of a market, hitting up every single customer with “You work in movies? You in show business?”

His auditions include “casting couch” come-ons and outright rejections.

But his head is turned by that one customer, soulful and sexy Carmen (Teresa Ruiz), whom he stalks to her Catholic Church. A manic “all-in” guy with a pseudo-charming patter — “How’d you find me?” “I asked God to help!” — Stu gives Carmen the full-court press.

“I’d wait 40 years in the desert for you.”

Standing out like a sore thumb at church doesn’t change Stu. He’s still a brawling barfly, still a foul-mouthed lout. And Carmen? She’s “a good Catholic.” She insists she’s not sleeping with him before marriage.

Modern redemption stories — on screen and in life — often hang on that one “big mistake” a character makes that turns a Chuck Colson or whoever towards religion. Stu’s is a tipsy motorcycle wreck that has the Virgin Mary visit him, lying on the pavement.

Next thing you know, he’s baring his coarse soul in confession, admitting he messed up in bedding Carmen, and deciding to join the priesthood.

Just. Like. That.

The movie, which gives us an hour of backstory to get to the point, is about how nobody takes Stu seriously, everybody questions his motives. There’s the shattered Carmen, who hoped to marry him, his foul-mouthed faith-hating mother and cynical, hard-drinking father, and eventually, his “You can’t fool God” fellow seminarians who rain on his Easter Parade.

Malcolm McDowell makes a fine impression as the aged monsignor reluctant to admit an older, problematic candidate with a lot of language and impulse control issues, and a police record. But with a common man’s grasp of faith and ability to cut through the flowery language to get at Biblical truths, Stu will not be denied.

It’s good to see Wahlberg showing some real ambition in a role, escaping the B-movie action pictures that seemed to be his career path of late. Weaver and Gibson are nicely paired-up and help give “Father Stu” that edge that I’ve long missed and complained about in this genre.

But Wahlberg’s patter performance highlights what a glib enterprise “Father Stu” is.

First-time writer-director Rosalind Ross leaps into features with a shallow, overlong picture on a colorful character who doesn’t lose much of that color as he is taught and severely tested en route to the priesthood.

“Father Stu” has funny, flippant dialogue and a smart, coherent visual strategy — lots of close-ups and extreme close-ups of one and all.

But there’s plenty of dead space, scenes that don’t advance the plot or just reinforce what we’ve already seen expressed and explained in many scenes before them.

The film has its best moments in the long run-up to the Big Conversion, and struggles afterward to justify “Why is this fellow worth a movie?” It climaxes with an agonizingly drawn-out finale that is neither touching nor definitive proof of why Father Stu got a pass to the priesthood or why this intimate, small world/smaller impact “personal” journey is worth over two hours of our time.

Wahlberg and the movie are likable enough, but overstay their welcome like a priest or pastor who never mastered the art of wrapping things up.

Rating: R for language (profanity) throughout.

Cast: Mark Wahlberg, Mel Gibson, Teresa Ruiz, Jacki Weaver, Carlos Leal and Malcolm McDowell.

Credits: Scripted and directed by Rosalind Ross. A Sony/Columbia release.

Running time: 2:04