Last month at the Columbarium funeral home in San Francisco, mourners gathered for the artist Frank Kozik, who died recently at 61.

The copper-domed rotunda on Loraine Court was filled with bikers and musicians from the Bay Area, along with artists who took part in the Lowbrow movement, the California pop surrealism scene from which Mr. Kozik emerged in his 30s. Some guests wore flannel shirts and leather jackets. One man with silver hair wore a Hells Angels vest.

In the 1990s, Mr. Kozik attained underground fame with his Day-Glo silk-screen concert posters for Nirvana, Pearl Jam, Nine Inch Nails and other bands, shaping the visual language for the grunge and alternative rock movements. In the early 2000s, alongside artists like KAWS and Futura 2000, he was a pioneer in the art toy boom, producing hundreds of mischievous animal figurines that became coveted by collectors.

Mr. Kozik’s best-known creation, a cigarette-puffing rabbit character called Labbit, is one of the most recognizable vinyl designer toys ever made. He released many of his creations with Kidrobot, a retailer that introduced art toys to the mainstream through collaborations with the band Gorillaz, the designer Marc Jacobs and the Museum of Modern Art. Outside Kidrobot stores, there were often lines for Mr. Kozik’s latest drops, predating today’s hypebeast culture.

As Mr. Kozik’s friends stood up to read tributes, a screen displayed his posters for Soundgarden and Sonic Youth, as well as images of his toys, like a Labbit branded with the anarchist symbol. A rendition of his 1993 Nirvana poster, depicting two children running across a field to hug an antennaed creature with bug eyes, accompanied the program.

At a gathering open to the public later that evening, Mr. Kozik’s fans would have the chance to mourn his death, but this ceremony was kept intimate. Sharon Kozik, his wife and business manager, watched while a friend read the eulogy Ms. Kozik had written.

“Frank built his life by making his own choices,” it said. “Tragically, for reasons I don’t know or understand, he decided to end his life on his own terms.”

Mr. Kozik died by suicide at his home on May 6.

“I know we all want reasons, but it’s not that simple,” Ms. Kozik said in an interview a week after the service. “There was Kozik, and then there was Frank.”

“When you look at his work,” she continued, “it’s funny, but it’s also dark and bold, and that’s how he was as a person. As far as his death, all I have to say is what was in my eulogy, which is that I don’t understand it. But I think it’s all right there in his work.”

Deconstructing Pop Culture

For 40 years, Mr. Kozik plucked imagery from American pop culture and twisted it into the playfully violent visuals that became his signature.

To illustrate a double bill for Stone Temple Pilots and Butthole Surfers, for example, he depicted a cherubic schoolgirl holding a bloody cleaver and a platter topped with Jerry Garcia’s severed head. He once designed a Labbit suited up in leather bondage gear, its mouth zipped shut. He used recurring motifs like Charles Manson’s mug shot, voluptuous devil girls and a hard-living, unshaven Fred Flintstone.

“All I do is consume the mountain of pap that surrounds us,” Mr. Kozik once wrote, “and extrude it in what I think is a more palatable form.”

Since his death, some of Mr. Kozik’s fans have been dismayed that his legacy hasn’t been recognized more prominently by the art world, especially on the East Coast, where many of its gatekeepers lie. But if the art community’s response has been muted, that has only solidified Mr. Kozik’s reputation as a roguish outsider.

“Kozik was a punk rock Warhol,” said the artist Shepard Fairey. “He was all about subverting culture. But whereas Warhol was hanging out with the Rolling Stones and the beautiful people, Frank was listening to Black Sabbath and chain-smoking and not making friends. Even his most famous character, Labbit, it might look cute, but it’s about subverting culture. Kozik saw his work as a Trojan Horse to grab people’s attention before reminding them that all is not perfect in paradise.”

“He wasn’t good at sucking up to the establishment,” Mr. Fairey continued. “The artists who enter art history are frequently the people sucking up to the people who write art history. I’d like that my work be remembered, so I’m willing to play the game to a degree, but Kozik didn’t have patience for that. To hear he’s now been unsung, I think, is something he’d have fun being bitter about.”

As Mr. Kozik told it in interviews, his penchant for defiance could be traced to his youth.

Born in 1962, he was raised in Madrid during Francisco Franco’s dictatorial regime. His father was an American serviceman, his mother a Spanish aristocrat. After they divorced, he grew up with his mother’s family, which he once described as a “weird, wealthy, super-old-fashioned household of fascists.” When he visited his father in California, he was tantalized by American pop culture, so he moved to live with him when he was a teenager.

In the suburbs of Sacramento, Mr. Kozik embraced the slackerish counterculture of the 1970s, holing up in his bedroom listening to Pink Floyd while reading comics like Heavy Metal. After a falling out with his father, who struggled with alcoholism, he dropped out of high school and fled his home. He joined the Air Force at 18 and was stationed at a military base near Austin, Texas. It was there, in the city’s punk scene, that Mr. Kozik found his calling.

After his military service, he worked in construction by day and immersed himself in venues like Club Foot and Cannibal Club at night. He tried joining a band but realized that he was a hopeless musician, so he started making fliers with a Xerox machine for local groups like Scratch Acid and Butthole Surfers.

He stapled his fliers to telephone posts around town, and people soon began to notice the scrawl at their bottom: “Kozik.” His legend grew when he made a copyright-defiling mural for a club called Emo’s: It depicted the Flinstone family and their pet, Dino, engaged in X-rated acts.

“I was part of the trash world,” Mr. Kozik said in a 2018 interview. “I was a no-education loser person and was definitely into hedonistic experiences. While I have an appreciation of fine art and I understand it, I was going to punk rock shows, not college nor museums. All of the stuff that really turned my crank was that stuff.”

“Be careful what you wish for,” he added. “Punk has informed everything, from low to high, in that everything is now atavistic. And that’s completely normal to the point where punk itself is the least interesting thing ever. It won, that dark side, the hedonism and anti-intellectual. ”

When Mr. Kozik began producing his giant silk-screen posters, he started receiving commissions from bands passing through Austin, including Red Hot Chili Peppers and Neil Young. Rolling Stone published an article crediting him with reviving rock concert posters as an American art form. He also directed the music video for Soundgarden’s “Pretty Noose” and designed the art for “Americana,” an Offspring album.

“It’s not an overstatement to say Kozik created the era’s visual language,” said Josh Homme, the frontman of Queens of the Stone Age. “If you were in an alternative band at the time, you wanted a poster by Kozik, because it was its own stamp of approval into the scene. And if your band was terrible, you weren’t going to get one.”

By the mid-1990s, Mr. Kozik had moved to San Francisco and pivoted to indie record mogul, founding Man’s Ruins Records, which put out some 200 albums, singles and EP’s by bands including Queens of the Stone Age, Kyuss, Melvins and High on Fire. Mr. Kozik created the artwork for the label’s releases. Man’s Ruins Records also had its own poster printing operation, and its warehouse headquarters became a hangout for the Lowbrow community.

But after a rapid expansion, it went bankrupt, leaving Mr. Kozik in search of his next metamorphosis.

He found it on trips to Tokyo, where the art toy movement was taking shape. A punk streetwear brand, Bounty Hunter, was distributing a limited-edition figurine of a boy wearing a skull and crossbones sailor cap, and teenagers were lining up outside its shop in the Harajuku district to get one. A toy company, Medicom, was also producing a plastic teddy bear with a paunch belly. Drawn to the medium’s possibilities, Mr. Kozik sketched Labbit at an izakaya one night, intending it as a play on Hello Kitty.

“The initial concept for the Labbit is he’s who Kitty booty calls at 3 a.m.,” Mr. Kozik said. “He’s unemployed, he’s dirty, he’s nasty, but he’s kind of hot.”

Soon he was designing various Labbits and other toys for Kidrobot, a company founded by Paul Budnitz, an entrepreneur from Berkeley, who was also enchanted by the craze.

At its peak Kidrobot had stores in London, Miami, San Francisco, Los Angeles and Manhattan. It collaborated on figurines with Snoop Dogg and MF Doom. Crossing into fashion, it released a set of toys that wore designs by Jil Sander, Dries Van Noten and Rick Owens, and Barneys New York sold a line of its sneakers and hoodies. But after Mr. Budnitz left the company, the brand’s edge dulled, and most of its stores closed a few years later.

Mr. Kozik was then appointed Kidrobot’s creative director, yet the scene was already transitioning into its next iteration. As the fine art world embraced the work of designers like KAWS, Mr. Kozik became a celebrity at conventions like DesignerCon and Comic Con. Collectors often cornered him to autograph their toys, and young artists sought his mentorship.

Ron English, a pop artist and toymaker known for his nightmarish Ronald McDonald figurine, considered Mr. Kozik’s legacy. “He’s the guy who was always there first,” he said. “He’s the guy who paved the highway so a KAWS could run down it.”

The Last Interview

As Mr. Kozik entered his 50s, he found himself in a fast-changing San Francisco. He lived in the same rent-controlled apartment that he’d moved into in the 1990s and spent his working hours in a studio above a motorcycle repair shop with the company of his Bengal cat, Eddie. He took on occasional poster jobs for bands like Primus and Blink-182, although designing toys remained his priority. He also became engrossed with NFTs, adapting Labbits into digital models.

After marrying a photographer, Sharon Selden, in 2009, some of his rough edges softened. “He’d developed his persona over the years, but he didn’t have to be Kozik with me,” she said. “He lightened up. I took him to a sugar egg making class. And he did something he once said he’d never do, which was come to Disneyland with me.”

But to his fans, Mr. Kozik’s punk stature loomed large, and he was characteristically stoic one afternoon in March when he sat at an arts center in Haight-Ashbury for what would be his last interview.

Wearing a black fleece with its sleeves rolled up, his forearm tattoos of sparrows carrying skulls visible, he talked with a Belgian filmmaker, Olivier Piérart, who is working on a documentary about the culture of rock concert poster design.

In the interview footage, which was viewed for this article, Mr. Kozik sips from a coffee mug and appears less than enthusiastic as he discusses the imagery he created three decades ago.

But his mood changed when he was asked a heavy question.

“Some people think you’re not appreciated,” Mr. Piérart said. “Do you know why?”

“If people don’t appreciate what I’ve done, that’s fine,” Mr. Kozik replied. “That doesn’t matter to me. I didn’t do it to be appreciated.”

He added: “This is who I am.”