Around a third of the way into this lengthy, discursive, at times deliberately shambolic documentary about the Irish singer-songwriter Shane MacGowan, a few of the film’s participants address a question that people have been asking about the man since at least the early 1990s: “How is this guy still alive?”

The answer seems to be that he just is. But a couple of interviewees insist that MacGowan’s prodigious drug and alcohol abuse (and general lack of self-care, long exemplified by MacGowan’s snaggletoothed maw of a mouth) is driven not by an appetite for self-destruction but a zest for life.

This ostensible zest and an undeniable love of Irish culture is conveyed in a stew of movie clips, animation, onscreen chats and archival footage — much of it from when MacGowan, now 62, led the Pogues, a band that put a punk stamp on Irish music and hit big with “Fairytale of New York,” a hipster Christmas tune. The director Julien Temple — who has excellent documentaries on the Sex Pistols, Joe Strummer and other galvanic musicians under his belt — is very good at this sort of thing.

As the movie’s subtitle, “A Few Rounds With Shane MacGowan,” implies, this is MacGowan’s show, not a conventional narrative on the music business. An inveterate “I did it my way” kind of guy, the singer, now wheelchair-bound, declined to be interviewed formally.

Instead he communes with famous friends, including the Sinn Finn leader Gerry Adams and the actor Johnny Depp, who’s also a producer here. (“What makes you think I was able to stay awake through ‘Pirates’?” MacGowan asks Depp, who starred in the “Pirates of the Caribbean” film series. “What makes you think I did?” Depp answers.) MacGowan’s indescribable laugh, mixing the least aurally attractive aspects of hissing and gurgling, makes him disquieting company even when he’s waxing mildly eloquent.

Crock of Gold: A Few Rounds with Shane MacGowan
Not rated. Running time: 2 hours 4 minutes. In theaters and on Google Play, Apple TV and other streaming platforms and pay TV operators. Please consult the guidelines outlined by the Centers for Disease Control and Prevention before watching movies inside theaters.