Maybe the most culturally significant rock band of the 1990s wasn’t Nirvana or Radiohead or Pavement, after all. Instead, maybe it was Dung Beetle, a satirical New York City punk trio that played only a handful of shows and released just one single. Of course, Dung Beetle’s members aren’t as important for the songs they made together as for what they’ve gone on to achieve. The band’s lead singer, who called himself Sam Shit, is now better known as Sam Lipsyte, one of the finest fiction writers in the United States, and the sound engineer, James Murphy, basically wrote the soundtrack to being young and cool in this century’s first decade.

Both men are in their early 40s, and they recently marked the occasion with meditations on being middle-aged and sad. The central character in Lipsyte’s superb new novel, The Ask, shares a voice with Murphy’s protagonists—they’re smart and acidic but paralyzed by their self-awareness. If Murphy’s new LCD Soundsystem album, This Is Happening, is about anything, it’s about waking up to realize that the world passes everyone by, even cynics. As he notes with a sigh on the album’s first song, “Dance Yrself Clean”, “Everybody’s getting younger.”

This is familiar ground for Murphy, whose first single as LCD Soundsystem, 2002’s “Losing My Edge”, brilliantly skewered a crotchety scenester’s hyperbolic defence of his cultural bona fides. Those lyrics were set to the kind of expansive, exquisitely recorded, and all-out euphoric backing track that would dominate nightclubs for years to come. This was dance music as pointed cultural commentary, a new mode that connected just as deeply with the Brooklynite’s world-weary contemporaries as with the young hedonists in the rear-view.

As the narrator of LCD’s songs, Murphy has always played a sad-sack hipster, smug in his own cleverness, but plagued by the feeling he’s missing out on something more meaningful. That sensibility pervaded his 2007 masterpiece Sound of Silver, which balanced shouty disco rave-ups like “North American Scum” with the sorrowful reminiscences of “All My Friends” and “Someone Great”. The LP was an inspiration of sorts for director Noah Baumbach’s new movie, Greenberg, which features Ben Stiller as a bitter ex-musician adrift in Los Angeles. The thematic connection between LCD’s music, Baumbach’s movies, and Lipsyte’s fiction isn’t lost on Murphy.

“It’s all stuff written by guys who are relatively the same age, facing the same doubts and questions,” says the singer, reached just over the U.S. border in Plattsburgh, New York. “It definitely seems like there’s some similar ideas floating around in the atmosphere. That’s one of the reasons I wanted to do the Greenberg soundtrack, because it seemed like it wouldn’t be that much of a stretch to get my head around this idea of writing songs to accompany this cynical character in his 40s.”

The score sounds unlike anything Murphy’s ever done before and, he says, unlike anything he’s likely to do again. Ranging from woozy instrumental lullabies (“Sleepy Baby”) to whimsical folk (“Birthday Song”) to Beach-Boys-circa-Sunflower choral pop (“Plenty of Time”), these modest sketches offer a glimpse of the New Yorker at his most contemplative.

The Greenberg sessions interrupted the production of This Is Happening, just as his work on 45:33 (his Nike-commissioned “workout” record) interrupted the making of Sound of Silver.

“I was hoping doing Greenberg would re-energize me to finish the album, but it didn’t work out like that at all,” he recalls. “45:33 had a lot of similar ideas that could be reflected in Sound of Silver in terms of it being beat music, and it helped me to work more quickly and not labour over everything so much. It freed me up, whereas the Greenberg songs are just so different in terms of tone and tempo and purpose; it didn’t really feed into this new album at all.”

Recorded in a Los Angeles mansion owned by Rick Rubin, This Is Happening documents a rock ’n’ roll fantasy and its aftermath, its gloriously messy tunes detailing the debauched night before (“Drunk Girls” and “Pow Pow”) and the remorseful morning after (“All I Want” and “I Can Change”). Those latter songs plumb deeper emotional depths than any Murphy’s ever written, their sophisticated concentric patterns suggesting he’s a better songwriter than he’s willing to let on.

“I don’t even know what being a good songwriter means,” he argues. “Better lyrics? Better song structures? It’s not something I have a really good grip on. I’m not really into songwriting, per se. I’m into energy.”

This Is Happening is certainly the most energetic LCD album to date, luxuriating in the pleasures of sound for sound’s sake—like the squalling guitars of “All I Want” or the crystalline synth patterns of “You Wanted a Hit”.

Murphy has announced that the disc is his band’s last, capping what might be the best three-album run in recent pop history. A drummer by nature and a punk rocker at heart, he’s always been a reluctant frontman, someone who’d rather recede into the shadows than become a professional pop star.

“When I was in punk bands, the bands sucked, but we didn’t have to do all this other crap you do when there’s more money involved,” he says. “With this band, we’re clumsy. It’s exhausting, and it doesn’t leave much time to have a life—to work on new projects, produce other people, and all the things I love to do. I feel like the band achieved a lot of stuff that I’m psyched about, but it’s not worth doing at the exclusion of everything else in our lives. It’s good to go out this way.”

LCD Soundsystem plays Malkin Bowl on Monday (May 31).