When tracking the career of John Sayles, who began writing and shooting low-budget independent movies long before it became fashionable, it’s clear he can be as much a muckraker as a filmmaker. Since his 1980 debut, the college reunion story “The Return of the Secaucus Seven,” Mr. Sayles has variously dramatized the bloody struggle to unionize West Virginia coal miners in the 1920s (“Matewan”), anatomized pre-war baseball scandals (“Eight Men Out”), surveyed dubious real estate dealings (“Sunshine State”), and examined political corruption and environmental hazards on the old frontier (“Silver City”). Taken together, his 16 original features view American life through a shifting, but knowingly sympathetic, prism of race and class.

But Mr. Sayles’s new film, “Honeydripper,” which opens next Friday, doesn’t feel like an Op-Ed commentary or a yellowed news clipping sprung to life. It has a more intimate, down-home agenda. Set in the rural town of Harmony, Ala., the story follows a very stressful week in the life of a juke-joint owner named Tyrone “Pine Top” Purvis (Danny Glover), who needs a miracle to save his struggling club. The year is 1950, and even this far back in the sticks, American culture is about to experience a radical jolt.

“What I wanted was a guy who was saved by rock ‘n’ roll, even though he didn’t know the name of it and wasn’t sure he even liked it,” Mr. Sayles said recently. Mr. Glover’s character is an old-school blues pianist who is losing out to the latest trend: the jukebox. An adjacent club is drawing all the business, which is flowing from the local Army base — reactivated as the Korean War begins to heat up — and the field hands flush from the cotton harvest. The sheriff is sweating him. He’s behind on rent. And his wife just wants Pine Top to come back to church.

“He’s got a lot of brush fires,” Mr. Sayles said. “He’s got problems caused by racism, economics, his own personality, and the dynamics of his family. It’s like a house of cards with 20 things trying to make it topple.”

When a young, vagabond guitar player named Sonny (Austin, Texas, musician Gary Clark Jr.) walks in, the house could go either way. Sonny, you see, plays electric guitar. Mr. Sayles, who was born in 1950, said he’d been thinking about a blues movie for a long time. The director is a serious enough fan that he can engage a visitor to his Hoboken, N.J., home with a knowledgeable pocket history of how the music transformed into something new — “Ike Turner is not mentioned strongly enough in the early story of rock ‘n’ roll,” he declared, rightly, at one point — and the social forces that propelled it. That’s much of what he winningly explores in “Honeydripper,” which revels in assorted aspects of black culture in the pre-civil rights South.

Because the film is self-financed and distributed, Mr. Sayles said, it took several years to accumulate the budget, which was eventually drawn from his salary as a screenwriter-for-hire (he has credits on the forthcoming “The Spiderwick Chronicles” and “Jurassic Park 4”). As with all his previous projects, Mr. Sayles collaborated with the producer Maggie Renzi, his longtime creative and romantic partner, who was busy upstairs in the offices of their film company, Anarchist’s Convention, when we met. The couple’s operation is such an intimate one that Mr. Clark, who had come up from Texas to promote the movie, had been sleeping in a guest bedroom.

That same spirit carries over to the movie. The cast, which includes Charles Dutton, Lisa Gay Hamilton, Vondie Curtis Hall, and the blues musician Keb’ Mo, brings the kind of life to Mr. Sayles’s screenplay that some audience members will identify with August Wilson’s dramas — deeply rooted in black-American traditions and the tug of history on individual lives.

“People came up knowing that there is a very low ceiling over what you can aspire to in the Deep South at that time as a black man,” Mr. Sayles said. “Every Saturday night and Sunday afternoon was when you transcended that world, either at the nightclub or the revival tent.”

“Honeydripper” was filmed at several Alabama locations, including Anniston, Greenville, and Hank Williams’s hometown of Georgiana, where the director got an earful about the country legend’s double life. “At the time he lived there, they considered him a juvenile delinquent and a wastrel,” he said. “Hank would pass out in a honky-tonk and they would drive him in his own car and leave him in the church parking lot, because he’d promised to sing there the next day.”

In “Honeydripper,” Mr. Clark’s rail-hopping guitarist quickly runs afoul of the sheriff (a treacherous, yet not all bad Stacy Keach) and finds himself picking cotton under the gaze of a gun-toting deputy. “It was very personal in those towns,” Mr. Sayles said. “Some of the people would have the same last name, black and white, and they knew why they had the same last name. So, of course, when somebody strange came through, like this kid with a guitar, they aren’t going to get through town without getting arrested.”

Ah, but the blues is about triumph over adversity, after all. Mr. Sayles, who is on strike from his paying job as a screenwriter, is hoping that “Honeydripper” will find its audience: several, in fact. The movie is being marketed heavily to black viewers, a demographic that has recently made hits out of Tyler Perry’s family comedies, as well as music-and-dance-themed entertainments such as “Stomp the Yard” and “Drumline.”

“We have our natural audience, which is relatively small and goes to non-Hollywood movies,” Mr. Sayles said. “And then you’ve got the music people into blues and R&B, which tend to be white guys over 40.” To reach them, some of the film’s musical cast — including Mr. Clark and blues veterans such as Eddie Shaw — are touring in the Honeydripper All-Star Band, with an original soundtrack album due from Rhino Records in February, when the movie opens in wider release.

Mr. Sayles is well aware of the success that the Coen brothers’ bluegrass odyssey “O Brother, Where Art Thou?” achieved through its soundtrack, which took the 2002 Grammy Award for Album of the Year. Music transcends even the vivid local color of the director’s best-loved films, some of which continue to generate a profit.

Such as “Lone Star,” for example. “It’s set in Texas,” he said. “There are a lot of Texans and they love things about themselves. ‘Matewan’ is popular in West Virginia, but there just aren’t that many West Virginians.”