Paying a visit to Claes Oldenburg, one of the last surviving giants of Pop Art, you’d be forgiven for expecting a wacky guy living in chaos. His crowd-pleasing masterworks — a canvas hamburger the size of a couch, a rusting clothespin as big as a house, a lipstick tall as a tree — can easily be read as giant guffaws at a pompous art world. His gorgeous sketches for those projects are as wild and woolly as could be. So yes, you’d be forgiven for expecting a scene from a shaggy New Yorker cartoon by Ed Koren — forgiven, and mistaken.

Mr. Oldenburg’s five-story studio, on the western edge of SoHo, is utterly tidy, its classic loft spaces furnished with rigorous Bauhaus classics and hard-edge Minimal pieces by Donald Judd. Mr. Oldenburg, who is 84, wears stylish round tortoiseshell glasses and receives his guest with more Old World gentility than New York pushiness. (He was born in Sweden, into a diplomat’s household.) He reveals a sense of humor, joking about how a big newspaper ad for his forthcoming show at the Museum of Modern Art, opening Sunday, has been upstaged by one for a show about whales. But there’s no trace of the clown, and there’s plenty of orderly retrospection.

“If you really want to be an artist, you search yourself, and you find a lot of it comes from earlier times,” he said. “I have pretty much built the work around my experiences. When I’ve moved from one place to another, the work has changed.” He came to New York in 1956 from Chicago, where he was mostly raised, and settled on the Lower East Side, which he describes as New York’s “most creative and stimulating part.”

His first notable art found its inspiration there, he said, in “garbage containers made out of burlap,” in the neighborhood’s nascent graffiti and in its competing Jewish and Latino cultures. And he was exposed to this street-smart energy at just the right time, when the showy abstractions of Jackson Pollock and Franz Kline felt old hat, but no one knew what was next. “It was a moment waiting to happen,” he said, listing all the artists ready to burst on the scene, like Red Grooms, Allan Kaprow and Jim Dine — not to mention himself.

That is the moment being explored in the show “Claes Oldenburg: The Street and the Store,” named for two projects that jump-started his career. Recreating scenes from the grit of New York’s urban fabric, originally as a backdrop for some of the first examples of performance art, Mr. Oldenburg’s early installations show a frenetic, angry, even political side that has been lost in our concentration on him in his later, cheery Pop Art incarnation. And that early work is perhaps in better accord with current art trends, giving Mr. Oldenburg a renewed relevance.

He is probably best known for the soft sculptures he made in the later 1960s, like giant fans and Popsicles and telephones sewn from floppy vinyl. Or as the man behind the massive public sculptures of the following decades, like a monumental pair of binoculars off Venice Beach, Calif., made in collaboration with his wife, the Dutch art historian Coosje van Bruggen, who died in 2009. But more and more, Oldenburg scholars are realizing that all that bubbly Pop had at its root his very early, angsty, urban works, like those coming to MoMA, and that his playful sculptures have more power when those roots are understood.

Ann Temkin, the museum’s chief curator of painting and sculpture and the coordinator of the Oldenburg exhibition — a more focused version of a show first seen at Vienna’s museum of modern art — referred to “The Street” (1960), Mr. Oldenburg’s first mature work, as “an absolute masterpiece.” It was an art installation before the term was current, shown for six weeks in a shabby basement gallery run by the Judson Memorial Church on Washington Square. Walls were covered with crude, barely legible cutouts of people, cars, bikes and guns — basic ingredients of life on the Lower East Side — made from found cardboard and slathered in black paint. The floor was awash in detritus picked off the pavements around Mr. Oldenburg’s home, and the whole mess also functioned as a backdrop for some of the earliest happenings. For the one called “Snapshots From the City,” Mr. Oldenburg dressed in rags and writhed and jerked amid the trash, finally pulling out a cardboard gun and miming suicide. “We were received in not too friendly a way,” he recalled. “We were changing the rules.”

Ms. Temkin said she detects an echo of Mr. Oldenburg’s early work in the rise of garbage art and abject assemblage today, as well as in performance. “I see a whole host of performances by artists in their 20s, and I’m convinced that they don’t know about these precedents,” she said. “They shouldn’t think they’re inventing the wheel.”

Mr. Oldenburg said he remembers when that was precisely what he and his peers were doing. “It all sort of coalesced as the ’60s came. It was magical, when you think about it, because everything seemed to start all of a sudden.” With the election of John F. Kennedy “there was a feeling that the country was going to come to life.” The artist’s job, as Mr. Oldenburg saw it, was to plug into that energy and to “engage our surroundings, to use the material around us in imaginative ways.” That engagement is what some younger thinkers now see as Mr. Oldenburg’s forte.

Joshua Shannon, 41 and a professor at the University of Maryland, is the author of an essay in a new volume on Mr. Oldenburg in the prestigious October Files series. He describes Mr. Oldenburg’s earliest art as bearing crucial witness to a moment when New York’s economy was shifting from the production of goods, as seen in the sweat shops of the Lower East Side, to financial services, advertising and other sponsors of the glass-and-steel skyscrapers that were leveling the old fabric of New York just as Mr. Oldenburg began to revel in it. (He said that he shuns skyscrapers to this day and pointed an accusatory finger at a rare one in SoHo that now fills the view from windows in his loft.)

“It’s a lot more complicated than just, ‘Hey, look, commercial stuff — I’m going to mix that with high art,’ ” Mr. Shannon said, which is the standard reading of what Pop Art is up to. Instead he said that Mr. Oldenburg was “more in touch with the underside of that economic moment; he’s around a fair amount of poverty and misery.” Mr. Oldenburg took the anger of Abstract Expressionism and redirected it toward sorrows found in the real world.

After all these years Mr. Oldenburg doesn’t reveal many traces of that earlier fire. He conducted an interview in a sweater vest and corduroys that would suit any retired professor. He talked, carefully, systematically, about the growth of his interest in color and consumer goods and about his lifelong insistence on form over content. (“I always say I’m not doing a hamburger, I’m doing a sculpture.”) But it seems almost certain that the methodical thinker of today has been in charge all along, even when his younger self was raging in rags or playing around with giant foodstuffs.

“The Store,” first fashioned in 1961 and Mr. Oldenburg’s second major project, was created as a mock shop at street level that he filled with funky plaster versions of his neighborhood’s everyday goods: bow ties, a bra and dresses, a cash register, even two cheeseburgers. By the next September, now in a gallery setting, these objects had been joined by huge, soft versions of an ice cream cone, a hamburger and a slice of fudge cake. For Mr. Shannon this work is bound up with “a basic bodily humanity” that was being “bulldozed” in precisely the place and at the moment that Mr. Oldenburg was making his art — that is, the old manufacturer’s world of making things with your own sweaty hands was being replaced by the new, immaterial service industries.

Mr. Dine, Mr. Oldenburg’s partner in art for some of the Judson happenings, sees another aspect to the story. Speaking by phone from his farm in Walla Walla, Wash., he noted his colleague’s European skills and touch (“it was so clear that Claes was a Nordic draftsman”) and stressed that it was Mr. Oldenburg’s origins abroad that gave him the distance to appreciate what was at stake on the Lower East Side. “He was looking at American consumer culture and finding New World romance,” Mr. Dine said.

This squares with memories called up by Mr. Oldenburg himself. He said he was happy to take on United States citizenship because “I found America most interesting, challenging.” Many of his sculptures refer to objects from the time of his arrival in America as a small child — to bulbous 1930s cars, tubby vacuums, clothespins — rather than to the brash world of 1960s consumerism that we associate with Pop Art.

Maartje Oldenburg, his daughter, cited a certain economic “foreignness” as a force behind her father’s interest in the Lower East Side. Ms. Oldenburg recently edited many of her father’s papers, and, aside from suggesting how fiercely disciplined and organized this presumably wild artist has always been (early diaries keep a daily record of his weight and diet), she said they show that, despite a pretty fancy upbringing — his father was the Swedish consul in Chicago; his mother sang opera — he has long been conscious of inequalities in wealth and power. “In his notes he’ll say, ‘I really side with the underdog,’ ” she said.

A visit to the Manhattan home of his younger brother, Richard Oldenburg, who retired as director of the Museum of Modern Art in 1995, gives some clue of how exotic New York’s tenements must have seemed to Claes when he first began to live among them: the apartment is full of the elegant Swedish antiques that the boys grew up with. Richard Oldenburg said that, in immigrant New York, young Claes “suddenly discovered that there was a whole world out there that he hadn’t dealt with.”

“It may have been in some general way a boredom with the bourgeois world,” he added.

So maybe now we’re onto what accounts for the peculiar nature of Mr. Oldenburg’s art and its longevity. He’s not seeing America’s popular culture through the eyes of someone born deep inside it, the way Andy Warhol did as a poor kid from Pittsburgh. Rather, Mr. Oldenburg came at that culture as a bit of an outsider, with a European’s eyes, and always saw it as bigger than it was and more full of magic than such ordinary subjects had a right to be.

“There was a lot of criticism for a long time,” Mr. Oldenburg said, recalling the pans of John Canaday, a critic for The New York Times, as especially harsh. “I remember how for one show he had a headline that said, ‘Oldenburg Is Back With a Few Bathroom Jokes,’ ” (The actual headline was meaner than he’s recalled: “Gag Man Returns With A Few Bathroom Jokes.”)

But then, Mr. Oldenburg said, he thought to himself, “O.K., say what you like, but you’ll see.”