On first glance, Michael Franti seems so relentless upbeat he might make your teeth hurt.

But he’s no Pollyanna.

The singer-songwriter, with a battered guitar — Mama Brown — that Willie Nelson would admire, is an activist whose R & B/reggae-flavored songbook that transcends his rap origins, says he wakes up thinking “the world is completely” screwed, just like the rest of us.

“The battle taking place today is between cynicism and optimism…I feel it in myself.”

An Oakland native of German-Irish-African-America/Native-American heritage, adopted as a baby, raised by a Finnish American couple, he could be excused for taking a more morose, Scandinavian pessimism as the posture he shows the world.

But he doesn’t.

As front-man for Michael Franti & Spearhead, he makes “socially conscious politically charged rap, reggae and acoustic music.” And he makes pop you can sing along to, tunes that have turned up in video games, on movie soundtracks. He’s toured with the likes of John Mayer and Stevie Wonder and played at Barak Obama’s inauguration and Bonnaroo.

His biggest hit is the lethally infectious, sing-along “Say Hey I Love You.” ”

Still, with all that success and an eco-resort (Soulshine) in Bali, he has his bad days. He questions his purpose, like any of us.

But he has these touchstones, people he’s found inspiring when his life needed inspiration.

“Stay Human,” which takes its title from one of his albums, is a documentary that has him traveling and interviewing those inspirations, and singing once he gets there. And what feels like a 50something pop star’s vanity project becomes — Dare I say it? — touching, as we meet the Atlanta couple who don’t let the husband’s ALS break their love, the natural childbirth evangelist in Bali, the a bamboo booster in Indonesia and two young South Africans overcoming poverty via education, and making a new future for themselves.

Robin Lim instills Franti with her belief that natural childbirth can reinforce “a child’s capacity to love and trust.” As she pitches in after a Philippine hurricane, a country where a huge portion of the population is pregnant, she declares “I want to live in a planet populated by people who were born gently.”

Franti, in dreadlocks and tattoos, driving a Tesla, is a veritable poster boy for progressive good intentions. He shows us his knee surgery and recovery and introduces us to Steve and Hope Dezember, Atlanta fans he met just as the “ALS Ice Bucket Challenge” was sweeping the land.

But Hope was contacting Franti because “Steve was living the REAL ‘ALS Challenge.'” He wanted to see a Spearheads show before he died.

As Franti gains a “Live your life to the fullest” perspective from them, we see him recording the moving ballad “Nobody Cries Alone.”

Arief Rabik is a surfing environmentalist and bamboo evangelist who is helping communities in his corner of Indonesia battle global deforestation by turning fast-growing bamboo into wood pulp that can be turned into planks and boards.

Rabik preaches that sustainability begins with “socially, having stability, then economic stability. Ecological stability follows.”

South African students Busisiwe Vasi and Sive Asinyo grow up in Port Elizabeth Township so poor that they live in a shantytown where a shared hose is the area’s only available water. But Ubuntu School encourages Busisiwe to avoid desperare shortcuts that trip up her peers and start her own business selling chicken, eventually finding her way to college.

Sive focuses on getting into college, too, and lifting his family out of a shared tiny shack.

Their stories, collectively “remind you of what it means to be your best, as a human being,” Franti says, who pulls out a guitar and sings with kids and adults wherever he goes. “Don’t you give up on me, and I won’t give up on you,” he sings, and you don’t.

He asks good questions, doesn’t overwhelm the film with his own story  and just oozes empathy and easygoing charm everywhere he goes.

Because he seems to fit in everywhere he goes.

“I want to make music that reminds me of the importance of the little things…that make us human,” he says. “Maybe our struggles are our greatest gifts. We are what we search for.”

It’s not a challenging documentary, and yes, “Stay Human” does have a touch of “write off my travels on my taxes/self-serving” promotion about it.

But heck, I’d vote for the guy. Or buy his “inspirational thoughts” calendar. I’m checking his tour schedule right after I hit “publish” here.

MPAA Rating: unrated, some profanity

Cast: Michael Franti & Spearhead, Robin Lim, Arief Rabik

Credits: Directed by Michael Franti. A Cinedigm release.

Running time: 1:34