When news arrived in my email box that “Don’t Turn Your Back on Friday Night,” a documentary about an Illinois-based singer-and-songwriter, Ike Reilly, was set to be released at the end of August, I burrowed into my closet and started unpacking the boxes of albums and CDs. Burdensome, they are, and essential. There are some reliquaries that Marie Condo and her deaccessioning ways will never have a purchase on.

Mr. Reilly’s debut album, “Salesmen And Racists,” was released almost a quarter of a century ago. My initial impressions of the record remain vivid and vexing. What was with this guy from suburban Chicago and his difficult-to-peg music? Rock ’n’ roll it most certainly was, especially with those hard-charging guitar riffs, but he’s also a bit country, punk-inflected, rap-adjacent, and, let’s face it, impertinent. Rude, one might say. “My songs,” Mr. Reilly tells us, “are either lies or apologies.”

Mr. Reilly had the temerity to begin the album with an ethnic joke masquerading as a song — that is, after explaining how a lack of sexual prowess was recompensed by a sterling sense of humor. The following number, “Hip Hop Thighs #17,” proved an irrepressible paean to Johnny Cash, Patsy Cline, and “the ex-lead singer of the Clash,” Joe Strummer. The latter, you see, had been handsy with the singer’s lady-friend. Mr. Reilly goes on to reassure us, and likely himself, that “no Limey ever made nothing like ‘I Walk the Line.'”

Snark isn’t Mr. Reilly’s forte, but he is acerbic and dependent on vernacular turns-of-phrase. He’s also possessed of an empathy that’s been both tested and strengthened by experience. At the beginning of the picture, co-directors Michael O’Brien and Mike Schmiedeler detail the backstory of one of Mr. Reilly’s signature songs, “Put A Little Love In It (According to John).” In doing so, they take us to the barber shop, the highway, and the graveyard, all the while confirming Mr. Reilly’s blue-collar roots and gift for the pithy aside.

A lot of time is spent in the artist’s birthplace, Libertyville. Has Mr. Reilly’s career suffered because he never left this modest township? That’s the theory of a musician, producer, and Harvard alum, Tom Morello, who, though New York City born was also raised at Libertyville. We watch as Mr. Reilly walks its tree-lined streets, navigating between local landmarks and the homes of friends and family. Although he’s toured the world on his own and with his band, the Ike Reilly Assassination, Mr. Reilly draws strength from being a hometown boy; not a little ire, as well.

While he is given to the excesses of the rock ’n’ roll lifestyle — Mr. Reilly and his cohorts do enjoy their tippling — the artist is blessed with a loving, infinitely patient wife, Kara Dean, and children who’ve grown accustomed to their father’s eccentricities and demands. “Don’t Turn Your Back On Friday Night” focuses, too, on rock ’n’ roll realities like paying the bills. Mr. Reilly has supported himself and his family by lawn-mowing, grave-digging, and door-manning. Not every rock ’n’ roll animal has been recognized by the Hyatt hotel chain as “Employee of the Year.”

Religion is touched upon. Born and raised Catholic, Mr. Reilly has since voiced his doubts about advocating on behalf of a “paternal religious army.” Still, he counts among his oldest friends Father Matt Foley, pastor of Mary, Seat of Wisdom Parish at Park Ridge, Illinois. The good bishop officiated at Mr. Reilly’s wedding, baptized his children, and continues to serve as a jogging partner. “It’s okay to disagree,” Father Foley tells us, “and it’s okay to remain friends.” He continues to pray for Mr. Reilly’s soul.

As cultural advocacy, “Don’t Turn Your Back on Friday Night” preaches to the converted: Messrs. O’Brien and Schmeidler come to praise Mr. Reilly, not bury him. Besides, Mr. Reilly is pretty good at burying himself: The picture doesn’t shirk from exposing the emotional and financial costs of staying true to one’s art. Would that the directors’ approach were less “impressionistic”: Upsetting the chronological arc of Mr. Reilly’s life and career results in confusing transitions, thereby denuding his story of clarity and drama. A ruthless editor could’ve made the film’s purview tighter.

The best place to acquaint yourself with Mr. Reilly’s flinty music is through the albums. “Salesmen and Racists” remains an unwieldy and irresistible signpost, but let’s hear it as well for “We Belong to the Staggering Evening” (2007) and the by turns salacious and tender “Hard Luck Stories” (2009). Should you find yourself emboldened by the artist’s raucous output, “Don’t Turn Your Back on Friday Night” will prove instructive.