Comedian Mike Myers really, really loves agent Shep Gordon. That’s what is most evident from “Supermensch,” his adoring documentary on the legendary talent manager. But the fact that the title is a weird amalgam of “Superman” and “Ubermensch” seems a foreshadowing of the fact that however much the film succeeds as a warmhearted tribute, it has some shortcomings that show Myers’ neophyte status behind the camera.

One of the problems is structural. The picture is a ramshackle, rambling affair in which, in the editing of Joseph Krings, we aren’t even told about Gordon’s difficult childhood until halfway into the running-time, and then in connection with a wraparound segment about the desire for a family of his own that’s presented as one reason for his becoming a surrogate dad to the three orphaned grandchildren of one of his ex-wives, Winona Williams, winning their undying gratitude in the process. Meanwhile, talking-head comments from some who have benefited from Gordon’s combination of uncanny skill at marketing and authentic personal concern for his clients—Myers himself, of course, but also people like Michael Douglas, Sylvester Stallone, Willie Nelson, Tom Arnold and Emeril Lagasse—are dropped into the mix rather randomly.

Their contributions, however, are modest compared to the extended excerpts from interviews with Gordon himself, who offers what amounts to a veritable memoir as Myers fills the screen with archival footage, zippy music and even comic recreations juiced up to have a period feel. An expert raconteur, though one with an unsettling tendency to chuckle annoyingly to himself, he recounts how he intended after college to become a probation officer but found that his counter-culture appearance didn’t endear him to his colleagues. Leaving his job, he found himself at a Los Angeles motel frequented by the likes of Janis Joplin, Jimi Hendrix and Jim Morrison and essentially fell into a managerial job.

But his major client in those early days was Alice Cooper, and “Supermensch” turns for long stretches into a Shep-and-Alice show, as the two men, with the help of archival footage and recreations, describe how Gordon shaped the performer’s persona as a representative of rebelliousness against the adult world into stardom (whether you consider that a triumph or a tragedy is up to you). Their friendship has prevailed ever since, and they still hang out together. An interesting juxtaposition occurs with Gordon’s decision also to represent Canadian singer Anne Murray, whose stage presence was close to the complete opposite of Cooper’s, but who received as much support from Shep as Alice did. A third major thread about Gordon’s business side centers on his representation of Teddy Pendergrass, whose career he took into the mainstream against long odds and nurtured even after the singer’s tragic 1982 auto accident.

But that’s not all. Myers also finds time to finger Gordon as the man who effectively created the celebrity chef, turning the renowned Roger Verge from a hired hand to a major draw and helping to invent the Food Channel. (One might dispute whether this should be looked on as a positive accomplishment, or a blight on the cultural landscape.) And he presents as a footnote Gordon’s role in early independent filmmaking. More significant, in terms of the man’s self-understanding, is Gordon’s acquaintance with the Dalai Lama (through Sharon Stone, no less) and devotion to the ideals he represents.

With all this, there’s little wonder that Gordon has so many gushing admirers, and Myers is as anxious as can be to present their encomia to him. Yet the film seems less self-aware than its subject. While Gordon occasionally expresses a hint of wistfulness and regret in his recollections, Myers seems reluctant to investigate any dark aspects to his personality. Gordon’s womanizing, for instance, is treated pretty much as endearing, as is his erstwhile embrace of the sixties drug culture; outsiders might have portrayed them in an edgier way.

Still, while “Supermensch” can’t be described as a warts-and-all portrait, it’s a generally enjoyable if rather messily constructed one of a canny showman and an all-around nice guy. At the very least it’s a lot more fun than, say, “The Love Guru.”