Earnestness combines with pedestrian technique in Martin Papazian’s well-meaning but clumsy film about a troubled ex-Marine redeemed by a paternalistic concern for an equally troubled young boy. “Least Among Saints” strives to be gritty and truthful, but it falls too far into the trap of sentimentality and implausibility to escape a contrived, formulaic feel.

Papazian may also have made a serious mistake by attempting to go the auteur route, not only writing and directing the picture but assuming the lead role himself. His screenplay offers some agreeably realistic sequences to balance the crudely obvious ones, and his direction similarly mingles authentic touches with an artificial striving for depth. But his performance as Anthony, the hard-drinking, suicidal vet who harasses his ex-wife and is in constant hot water with the cops, never gets beyond the semi-amateur level. He tries very hard, but what’s apparent is the trying, not a convincing result.

That’s clear from the superior turn by young Tristan Lake Leabu, who gives Wade, the ten-year old son of Anthony’s next-door neighbor Cheryl (A.J. Cook), a welcome degree of naturalism and warmth, despite pressure from director Papazian to push the emotional buttons too firmly. When Cheryl, a battered wife with a drug problem, overdoses, it’s Anthony who takes her and Wade to the hospital, where he begins the bonding process with the kid.

At this point the hard-to-swallow aspects of the script kick in, as the harried social worker (Laura San Giacomo) tasked with finding a temporary home for Wade agrees, reluctantly, to let him stay temporarily with Anthony, despite the fact that his house is a mess (especially the garage, where he made the mistake of trying to hang himself from a beam that couldn’t support the weight). What follows is an increasingly unlikely series of episodes, in one of which Anthony instructs Wade about how to handle a schoolyard bully (opening himself to charges of assault in the process) before taking the boy on a road trip in search of his dad, during which he actually decides to teach the kid how to fire a rifle. Of course, Chekov’s dictum about having to use a gun as a plot device after introducing it eventually comes into play.

All of that, however, is merely prelude to a last act that goes to simply incredible redemptive lengths, thanks to a remarkably indulgent police chief (Charles S. Dutton) and San Giacomo’s amazingly soft-hearted government employee. “Least Among Saints” ends with a feel-good coda that takes it into territory it’s not unreasonable to refer to as sheer fantasy.

Even Dutton and San Giacomo are far from their best in Papazian’s effortful fable of ruined lives restored by care for one another, which is technically mediocre to boot. Even if you agree that everyone can be a saint, this isn’t the movie you should choose to confirm that belief.