The mystique of Miles Davis was rooted in the sinister magnetism of his character as much as it was in the nocturnal genius of his music. His nickname was ‘Prince of Darkness’, and in the ‘50s he was a hypnotic reptile of cool, with sunken cheeks and a killer stare that said, “Don’t mess with me.” By the late ‘70s and ‘80s, with his tangle of long hair, regal-pimp wardrobe, and iconic rasp (the result of raising his voice too soon after a throat operation), he’d become a deeply transgressive figure, infamous for his drug abuse and violence against women, with a dissolute rock star’s mystery and danger. He seemed like some magnificent creature that had crawled out of a swamp – the ultimate midnight badass.  Miles Ahead, a free-form biopic directed by its star, Don Cheadle, is a passionate jumble of a movie, a heady plunge into Miles Davis’ persona that doesn’t always bother to make sense of what he did or why he did it. At the center of the film is Cheadle, who slithers deep inside the croaky Davis charisma. Eddie Murphy on Saturday Night Live once memorably compared Davis to a Gremlin, but Cheadle, with lethally pursed lips and iceberg eyes, gets beyond the comic kitsch and recreates the fabled Davis mannerisms in all their ferocity: the stare that turns every encounter into a showdown, the rasp as quietly threatening as Don Corleone’s. Damned if he doesn’t make the man as fascinating as he really was.  The film opens in the late ‘70s, when Davis, holed up in his townhouse on Manhattan’s Upper West Side, has become a scraggly hermit who has spent the last five years in seclusion without performing or issuing any new recordings. He has now made one, though: a secret session at Columbia Records that has yielded a tape the company wants, and which winds up being stolen from Davis during a party at his home. His attempts to get it back – a wild downtown car chase, showdowns at gunpoint – are the frame for this raucous, frazzled section of the movie, which at many points had me siding with Columbia. The company owns the tape, which Davis treats as a rare artefact of his timeless genius. But is that his jazz purity speaking, or it just his crazed, drug-fueled ego? Watching Miles Ahead, we can scarcely separate the two.  The movie keeps leaping back to the ‘60s, when Davis, having made the 1959 cool-jazz epiphany Kind of Blue (now the best-selling recording in the history of jazz), had become a superstar. What he chooses to do with his freedom and clout is to lord it over everyone in his midst – and that includes the love of his life, Frances Taylor, played by Emayatzy Corinealdi as an elegant baby doll out of a Mad Men daydream. Taylor is a gifted dancer who Davis marries and then wants to possess. He forces her to stop dancing and rubs his womanising right in her face. And when she protests, he beats her up. Why?  In contrast to a great biopic like Get on Up, which rooted James Brown’s inexcusable behavior in his complex reaction to racism and his own childhood abandonment, Miles Ahead lacks any true psychology. It basically says: Davis was a raging tyrant – deal with it! The spectacle of his bad behavior can be horribly transfixing, as bad behavior in biopics so often is, yet the movie needed to give us a richer sense – some sense – of the source of his demons.  Davis’ ultimate act of heartbroken fury is to withhold his talent from the world  It’s the late-‘70s Miles, for all the slapdash staging of this section of the movie, who we can relate to the most, because there’s a vulnerability that keeps peeking through his tattered facade. He hooks up with a disheveled reporter (Ewan McGregor) who wants to do his comeback story for Rolling Stone, and while this feels like the creakiest device imaginable, Cheadle and McGregor actually develop a compelling chemistry. As the reporter helps Davis score some drugs from a dorm-room dealer, then heads back to Miles’ place for a late-night confessional coke binge, we begin to see that Miles Ahead is really a comedy of depression. The Davis we see has made a mess of his life, and he’s suffering for it, but his ultimate act of heartbroken fury is to withhold his talent from the world – to say, “You don’t deserve me.” Can he get over himself?  In the end, he does, though I wish we’d seen with greater precision how it happened. The closing credits feature Cheadle’s Miles in concert during the early ‘80s, wearing a leather jacket with an insignia that says #SocialMusic. “Social music” is the term that Miles thinks should be used instead of jazz (“a made-up word,” he says derisively), but all I could think was: nothing was marked with a hashtag in the ‘80s! Surely Cheadle knows this, but the idea seems to be that as a filmmaker, he can be as loose and improvisatory as he wants to be. He may even think that he’s working in the spirit of jazz. But biographical dramas, unlike jazz, need to be grounded in reality. And Cheadle’s performance, while it makes Miles Ahead worth seeing, should have been grounded in a more focused and tough-minded movie.  If you would like to comment on this story or anything else you have seen on BBC Culture, head over to our Facebook page or message us on Twitter.
The great jazz trumpet player’s drinking, womanising and drug abuse are all on show in the new film Miles Ahead. But the film never gives us a convincing reason for his bad behaviour.