Amid the many surreal highlights local director Brett Harvey had shooting Inmate #1 was cruising around L.A.’s Pacoima ’hood in Danny Trejo’s gorgeously restored ’56 Chevy Bel Air.

At the wheel, the famously bad-ass tough guy who’s perfected the death stare in cult hits like Machete and Desperado would wave gleefully at passersby and point out his old hangouts—including the first stores he robbed as an elementary-school heroin addict.

“He literally lives in the same neighbourhood where he grew up—and everywhere we went people would be yelling out ‘Machete!’” the Burnaby filmmaker recalls to the Straight.

“I remember entering Danny’s neighbourhood for the first time, and just all the murals that were there, and the culture, and the heat,” he adds of the racially diverse San Fernando Valley community. “It was a very different world. And then to have Danny take us deeper into that world, talking about these personal stories.”

They add up to the kind of tale you can’t make up. Born in 1944, Trejo took his first hit of heroin at just 12, spent his teens as an armed robber, and put in hard time throughout the ‘60s. He became a champion boxer at San Quentin prison, then worked as a drug counsellor. That was all long before his first film gig, as an extra in the prison scenes for Runaway Train in 1985. There, screenwriter Eddie Bunker, himself an ex-con, recognized Trejo as a jail legend and asked him to train the film’s star Eric Roberts to box in the movie.

Trejo has gone on to become one of the stone-cold scariest dudes onscreen—whether he’s flying through a ball of flame firing a military-grade machine gun mounted to his motorcycle in Machete, or sending a barrage of blades from his well-stocked knife belt into Antonio Banderas and Steve Buscemi in Desperado. In one of Inmate #1’s more memorable quotes, Con Air star Nicolas Cage is recalled deeming Trejo the one genuinely frightening guy out of all the pedigreed bad guys collected for the cast of airborne criminals.

Harvey, who made the new documentary with Canadian producer Adam Scorgie, is used to tough guys after making films like his hockey-enforcer documentary Ice Guardians. But the Trejo he found was constantly laughing, endlessly generous, and beyond inspiring.

“One of the things Danny had to learn was how to disarm people immediately,” Harvey explains. “He came out of prison with that look of ‘I’m gonna kill you.’ It was Eddie [Bunker] who told him, ‘Danny, when you come onto set people are scared of you. So when Danny walks into a room now he says ‘Hello! How are you?’ with a big smile.

“He’s joking constantly,” he adds, “and I think that’s because he didn’t really have a childhood. When you think of it, the majority of the stuff he does now [onscreen] is comedy.”

The film is packed with colourful anecdotes, not just from Trejo colleagues from Robert Rodriguez to Cheech Marin, but from the well-inked title character himself. Choice tidbits range from a dope-addled teen attempt to rob an electronics store with a hand grenade to re-enacting the entire plot of The Wizard Of Oz while trying to stay sane in a shit-smeared solitary cell.

In the film, Trejo talks about how learning to give instead of take was the key to his own recovery. “Everything good that’s ever happened to me came out of helping others,” he says.

And now he passes that message on to others. His capacity to inspire is no more evident than in the scene that bookends Inmate #1, one where Harvey’s cameras follow the fedora-bedecked star into a room full of orange-jumpsuited inmates at Arizona State. Preternaturally spry and never looking his 76 years, Trejo tells them how he escaped a life behind bars.

“The thing about Danny is his life after prison became a search for redemption,” Harvey says. “It was, ‘How can I give back now without expecting anything in return?’ He realized it’s not an end game.

“That’s why everyday right now Danny is giving out food to first responders,” he says of the star, who runs a popular taco and cantina chain in L.A. “And when Danny does a film now he asks his managers to look up the prison in the area so he can go there and speak.”

An outstanding human being, for sure, but it must have been a little bit intimidating presenting Hollywood’s baddest bad guy with the first cut of the film, right?

Screening Inmate #1 in L.A. for Trejo and some family and friends, Harvey says, “I had a pretty good feeling he was liking it; he kept nudging his bodyguard saying, ‘Look at that!’”

And then, when the lights came up, he says the star stood up, stonefaced, turned to the small crowd, and announced in his best don't-fuck-with-me gravelly deadpan: “I am Danny Trejo and I approve of this movie.”

Inmate #1: The Rise of Danny Trejo is streaming now via Super Channel, iTunes, Amazon, as well as other digital platforms.