In “Palmer,” Justin Timberlake plays an ex-con, a hard man who comes back to his hometown and the grandma who raised him, looking for a second chance.

But that second chance doesn’t really present itself until his granny (June Squibb) dies, and a little boy with a feminine air she’s been looking after requires Palmer to soften, develop tolerance and compassion and think of somebody else for a change.

It’s a role with a lot of silent, sullen brooding built in. And in the hands of actor turned director Fisher Stevens (“Stand Up Guys”), it’s never much more than a “star vehicle” in the classic sense — lots of close-ups of Palmer’s thousand-yard-stare, tank tops showing off the tattoos, a sex scene and out-of-his-league romance, and sympathetic moments of a fatherless ex-con easing into fatherhood.

Not terribly demanding, in other words. But Timberlake is intensely likeable in the part, and that makes it work.

Palmer used to be somebody in Sylvain, Louisiana, a star footballer who left to take a scholarship at L.S.U. But life went off the rails for “Eddie,” and now he’s back where they know him, and how he went wrong, to start over. He’s just Palmer now, and while Grandma Vivian makes him go to church with her to “get yourself back out there,” he’s inclined to make “out there” Benny’s Place, the local bar where his old cronies hang.

And that single-mom living in Granny’s rental trailer out back? She’s played by Juno Temple, who has made a career out of loose, “nothing but trouble” train wrecks who are DTF with the leading man — in the film’s first act.

But Shelly’s son is different. Sammy (Ryder Allen) is about 8, dotes on his mom and on those occasions when she skips town on a bender, Palmer can find him doing Grandma Vivian’s hair, losing himself in his favorite fairy princess TV show and getting bullied by the locals for it.

As the only place that’ll hire an ex-con is the elementary school that needs a janitor — and that takes an intervention from a sympathetic principal and compliant school board — the disinterested Palmer witnesses Sammy’s life up-close.

And when Grandma Vivian dies, Palmer faces what could be his first responsible adult decision — dump the kid at the police department (Mom’s been gone a month) and into “the system,” or look after him.

Timberlake’s look in this film does a lot of the heavy-lifting for him. Muscled-up, with a beard and Farm Supply cap pulled down over his eyes, he’s the spitting image of Ben Foster. Foster plays a lot of hardcases.

But he manages the transition well, and in a lot of crowd-pleasing ways. A fatherly bit of business — Palmer asks Sammy if he’s taken a bath, assured he has, he tugs him by the shirt, takes a sniff, and begs to disagree. The kid’s cute and sympathetic and Timberlake does a nice job of taking Palmer on the journey from “not my problem” to father-figure.

You can’t let yourself think too much about Sammy’s beautiful teacher (Alisha Wainwright of TV’s” Shadowhunters”) taking a shine to the rough-hewn ex-con janitor, or about the nature of the crime that sent Eddie to prison and brought him back as Palmer.

Cheryl Guerriero, who has a Paris Hilton movie among her screenwriting credits, hews to a formula and doesn’t sweat the implausibilities.

But if “Palmer” isn’t that demanding of star and audience, it’s a perfectly serviceable story for at least reminding the film world that you’re out there, available and perfectly capable of delivering the dramatic goods.

MPAA Rating: R for language, some sexual content/nudity and brief violence 

Cast: Justin Timberlake, Ryder Allen, Alisha Wainwright, Juno Temple and June Squibb

Credits: Directed by Fisher Stevens, script by Cheryl Guerriero. An Apple Original release.

Running time: 1:50