As acting “baggage” goes, you could do worse than be saddled with the rep Jason Segel takes with him from film to film.

He’s carved out a niche playing softies, pushovers, semi-lost souls who go through life always erring on the side of “sweet.” From “Forgetting Sarah Marshall” to “Jeff Who Lives at Home,” years on TV’s “How I Met Your Mother” and in the new film, “Our Friend,” he’s the best friend you’d ever want to have, the sensitive one who may be “lost” but who always has time to help you find yourself.

“Our Friend” doesn’t lose track of its title character, but it does wander around him an awful lot as it skips through time, tracking a marriage from its early days through the terminal cancer that takes the life of the wife and mother. That diffuse focus and meandering narrative is the only real shortcoming in this consequential and touching weeper, a film inspired by a true story written by the magazine journalist who survived that loss, largely through the semi-divine, half-aimless intervention of “Our Friend.”

Dane (Segel) doesn’t make a great first impression on Matthew (Casey Affleck). He’s a stage hand at the New Orleans theater where Nicole (Dakota Johnson) is in a play, the one stage hand with the temerity to ask her out.

He didn’t know she was already married, and Dane’s disarming, hangdog self-loathing is all it takes for Matthew to take to him, just as his wife as.

In a narrative that skips back and forth through time, we see Nicole and Matthew early in the marriage, when Matthew is starting his journalism career at the Times-Picayune and she is acting, the period right after her cancer diagnosis, then back to later stops on Matthew’s globe-trotting career path, then the day a doctor tells them “It’s terminal.”

Parties and birthdays, plays and assignments overseas pass by. And Dane? The die is cast the first time he’s asked about his ambition. He’s an aspiring stand-up comic. How’s that coming?

He’s “started to think about it.” He’s looking ahead to the day when “I get a pen, get a pad,” and starts writing funny ideas and jokes down.

That’s Dane. A little dreamy, a little lonely, seriously self-defeating. That’s Dane even after he finally gets a serious girlfriend. He moves in, but almost to the day that’s when he dashes down to Fairhope, Alabama where the his friends and their two little girls have settled. Nicole’s gotten sick, and Matthew, trapped and lost in a domestic crisis beyond his grasp, has let the house go to pieces and left the girls (Isabella Kai, Violet McGraw) to half-fend for themselves.

“Would it help if I stayed for a while?”

Yes. Yes it would. And as the couple wrestles over “when to tell the kids” and Nicole’s impulsive and near-impossible “bucket list,” the guy Mom nicknamed “Fruit Loop” way back when, who now insists the kids address him as “Grandma Dane,” steps into the void. He might be an aimless, rootless 30something, but he’s well-stocked with “Dad jokes.”

“Me? I didn’t do nothing. I’m like the Mona Lisa. Framed!”

He’s there to get the kids to school, leading sing alongs to “Call Me, Maybe,” to take the dying dog to be put down. His girlfriend may be frustrated, and Dane’s own issues — visited throughout the time periods of the story — make us and him wonder if he has the stamina to “help you get to the other side of this.”

Director Gabriela Cowperthwaite, who transitioned from documentaries (“Blackfish,” the movie that ended orca captivity at SeaWorld) to features (“Megan Leavey”) has her own brand, making movies of emotional substance.

She lets Segel stay in his comfort zone and do bits of cute shtick with the kids, but never lets us forget what Nicole is going through and how that is pummeling everyone around her. The oldest daughter (played by Kai) knows what is happening and is acting out. Earlier strains in the marriage might re-open. Matthew had a fainting problem earlier on, and as doctors and others (Cherry Jones plays an angelic hospice nurse) in the know realize, as the illness progresses, friends are “going to fall away, one by one.”

The downbeat tone and constant shuffling of the order of events in the narrative only makes the viewer forget where the real center of gravity is here. But as disorienting as that is, it’s reinforcing, in a way, what the laid-back manner of Dane’s introduction sets up as its message.

Sometimes, it’s the last people you expect when you first befriend them who stick around. And when the chips are down, their biggest surprise for you is that they’re the very last ones to leave.

MPA Rating: Rated R for language

Cast: Dakota Johnson, Casey Affleck, Isabella Kai, Violet McGraw, Denee Benton and Jason Segel

Credits: Directed by Gabriela Cowperthwaite, script by Brad Ingelsby, based on an article by Matthew Teague. A Gravitas Ventures/Universal Home Ent. release.

Running time: 2:05