When notice of the new documentary by Peter Michael Dowd appeared in my email box, I clicked on the link, scanned its contents, and summarily deleted the message about “Mr. Jimmy.” As someone suspicious of nostalgia and the squishy comforts it proffers, the last thing I wanted on my docket was a film about a middle-aged man who has spent the greater part of his life trying to recapture the heady buzz of adolescence. 

Why I later retrieved the missive from the good folks at Abramorama, a distributor of offbeat films based at Pleasantville, New York, I don’t know. The title of Mr. Dowd’s picture refers, at least in part, to Jimmy Page, the British musician who, sometime in the late 1960s, formed the band Led Zeppelin. Perhaps you’ve heard of them.

Led Zeppelin’s music, though an inescapable part of the cultural landscape during my teen years, never suited my taste. It was only in middle age that I understood the inherent humor in the band’s enterprise. With their admixture of gargantuan riffs and folky medievalisms, Mr. Page and his cohorts set out to create the musical equivalent of a brontosaurus attempting a pirouette. Pursuits as inherently quixotic as that can’t help but garner some admiration.

“Mr. Jimmy” is similarly quixotic in its detailing of the life and ambitions of Akio Sakurai, a Tokyo-based kimono salesman who has spent 30 years proselytizing on behalf of Led Zeppelin and, in particular, Mr. Page. Physically, Mr. Sakurai is all but a dead-ringer for the guitarist as he appears in the 1976 movie, “The Song Remains the Same.” The spindly frame, the generous mop of hair, and a similarity in facial structure — pair all of that with body language that speaks of hours spent studying concert footage, and Mr. Sakurai more than earns the title sobriquet.

But, then, Mr. Page is also a musician, and it’s testament to Mr. Sakurai’s powers of concentration and indomitable drive that he proves almost as walloping a talent on the guitar as his hero. “What’s amazing about ‘Mr. Jimmy’ Sakurai …,” the founder of a custom guitar workshop, Makoto Fukano, says, is that “he’s maintained that passion since he first heard [Led Zeppelin] and that initial shock.” “Obsessive” is a word bandied about a few times during the course of the film, but Mr. Sakurai’s ardor for all things Zeppelin is indicative less of neurosis, I think, than of love.

This isn’t to say that his venture is without its quiddities or that he isn’t a piece of work. Mr. Sakurai is a scholar, a purist, and a perfectionist. What doesn’t he know about Led Zeppelin? Forget the albums, the bootleg CDs, the films and books. There are also the guitars, the amplifiers, the cords, the bobbins, and the Les Paul pickup guards with their angular edges and scalloped holes replicated by Atsushi Iwasaki and Naoki Washida, craftsmen of boundless patience and impeccable skill. If you’re working for Mr. Jimmy, the last two attributes are musts.

Then there’s the Black Dragon suit worn by Mr. Page during Led Zeppelin’s 1975 tour. Mr. Sakurai has tasked both his wife Junko and Kiyomi Osawa, a Yokoburi embroiderer, to replicate the outfit. Every last stitch is accounted for; colors are gainsaid, double-checked, and ultimately put in order. Among the electrical technicians with whom Mr. Sakurai works is Kishimoto, a man of sober temperament who’s got a pretty good peg on his client: “Ultimately he’s going for something that doesn’t have an answer.”

When Jimmy Page — not a simulacrum, but the man himself — shows up for one of Mr. Sakurai’s gigs, well, things change. Mr. Jimmy packs his bags, heads to the United States, and plies his trade in a tribute band called Led Zepagain. Whereupon follows a clash of egos, of cultures, and, not least, of artistic purpose. 

Mr. Sakurai’s unbending adherence to Led Zeppelin’s music is called into question. He loses faith, money, band members, and friends. How this story pans out is better left unspoiled, but the trip Mr. Dowd has chronicled has keen things to say about the perils of the creative life, the imperishability of art, and the rewards that come with persistence. “Mr. Jimmy” is a deceptive and, in the end, peculiarly profound motion picture.