The late great Bob Marley’s music has been in the air for so long that it takes some effort to ponder a time when it didn’t exist. But long before reggae became stoner wallpaper for hacky sack enthusiasts, he was just another musician trying to be heard – even if his hardscrabble circumstances were more dire than most.

“Marley,” director Kevin MacDonald’s epic and fascinating documentary about the reggae king, manages the remarkable feat of covering all the bases from large to small. It’s fittingly grand, giving a scale of just how massive a figure Marley was and is; he was an icon who could inspire cease-fires because both sides worshipped him, with an appeal spanning cultures, continents and now time. Only Muhammad Ali and Michael Jackson rival him as 20th-century black popular culture’s greatest figure.

At the same time, “Marley” is chock-full of details that make his story palpable. You’ll get something from this film no matter how much or how little you think you already know about the man.

It’s all the more remarkable how well “Marley” turned out, given that MacDonald is the project’s third director (after Martin Scorsese and Jonathan Demme both bowed out), a telltale troubled-production red flag. Throw in the film’s 2 1/2-hour length and the Marley family’s involvement, and you have a recipe for indulgent hagiography.

Yet “Marley” is anything but, portraying its subject and his life as both brave and flawed. It’s full of larger-than-life interludes, yet some of the film’s most emotional moments belong to his daughter Cedella, whose disappointment in her father is still evident 31 years after his death.

After showing an African slave port, “Marley” moves to its subject’s Jamaican homeland with stunningly beautiful fly-over shots of the misty rural hill country where he grew up. Born of mixed race to a teenage mother and a white British soldier in his 60s, young Bob grew up as a “half-caste” who had to earn every meal and was not accepted by either side.

The fire that stoked within Marley would never abate. One of the film’s most poignant scenes shows two of Marley’s white relatives listening to “Cornerstone,” a song inspired by his white family’s rejection of him. Clearly shaken, his half-sister notes the irony that Bob is the Marley the world knows now.

More than three decades past Marley’s death, you’d think his trail would be pretty cold by now. But “Marley” presents an amazing and varied cast going all the way back to his mother and first schoolteacher, along with various friends, relatives, lovers, associates and even a few neighbors in the Delaware town where he worked for a few years as a forklift driver at the Chrysler plant. In people’s descriptions as well as period footage of Marley onstage and off, his charisma is apparent.

The music is, of course, amazing. “Marley” does a fantastic job of putting it in context as an outgrowth of ska, with elements drawn from gospel and American pop and soul. In early photographs of Marley’s band the Wailers, they look like the Temptations in their matching suits. Marley’s bandmates get plenty of camera time, too, especially Bunny Livingston’s soft-shoe demonstration of reggae’s signature rhythmic style (perfectly synced to the background music).

“Marley” touches on its subject’s ramblin’ ways and the unseemly post-death squabbling over his estate without dwelling on either too much, which is honestly just as well, because it ultimately doesn’t matter. Even knowing that Marley had 11 kids (confirmed, at least) by seven different women, you just can’t resist the man as he’s presented here. As one of his girlfriends summarizes, “We still couldn’t hate him for it.”

As you’d expect, live-performance scenes are a big part of the film, and “Marley” has some great ones. The 1978 peace concert in Jamaica, where Marley brought the country’s main political rival leaders onstage and made them clasp hands as his band throbbed away, remains an incredible piece of political as well as musical theater.

Throughout, MacDonald’s attention to detail is impressive, cannily interweaving archival footage and photos with modern-day scenes and a killer soundtrack. As the camera traverses the numbered streets of Kingston’s Trench Town district, the song playing is “Natty Dread,” with lyrics counting off those same streets. And the gospel-style demo of “No Woman, No Cry” with Peter Tosh on piano adroitly shows Marley’s debt to American spirituals.

But popular music’s debt to him is still far greater. See this film and find out just how much.

Menconi: 919-829-4759 or blogs.newsobserver.com/beat