At the department store, introducing her installation there in January, Ms. Longshore, 46, lured a crowd of mostly young women scrambling for a chance to view the art and the artist, up close. They jostled, scarcely registering the presence of the actress Blake Lively, one of Ms. Longshore’s most ardent collectors; the designer Christian Siriano; and celebrity stylists including June Ambrose and Jenke Ahmed Tailly, who counts Beyoncé and Kim Kardashian as clients. Single-mindedly they snaked toward Ms. Longshore, who stood at the rear of the room dispensing hugs.

“I love her, she captures a lot of positive vibes,” said Cara Dimino, 24, a medical researcher from New York, as she threaded her way through the crush.

Lisa Burwell, the editor ofVie, a West Coast-based style and culture magazine aimed at 25-to 35-year-olds, called the artist “a pied piper of hope and fun.” The world, she said “just doesn’t have enough of that.”

Birkin Bags and Diamond Bracelets

Ten days later, back in her studio and gallery here, Ms. Longshore grinned nakedly. “Boy, did I freaking bring it,” she said. Her ardor, she knows, is infectious. “All those girls at the opening, I want them to feel, ‘This could happen to me too,’” she said, adding, with no trace of irony, “My greatest legacy is not my painting but sharing with them that feeling of endless possibility every day.”

Ms. Longshore recently published a book, “You Don’t Look Fat, You Look Crazy,” a combination of self-help and memoir dense with her bawdy illustrations, rejoinders and briny aphorisms. “Just womanup,” she urges, interjecting curse words. “Put on your big-girl panties and deal with it.” Or, more philosophically: “No one should be devalued because of their genitalia.”

Earlier this month an eye-popping blowup of her recent Vie Magazine cover loomed over Times Square. “No words!!!…No words to describe…,” she rhapsodized in an Instagram post.

A professed mega-consumer, she dotes on her Birkin bags, which, to those who can afford her work, may be part of her allure. “She is about living the good life, about high style,” said Alan Bamberger, an art consultant in San Francisco. “She says it’s O.K. to be lavish, to own expensive things. She doesn’t apologize.”

Ms. Longshore’s sparkly rings andChristian Louboutin shoes add some “lady” to her look, a brash hybrid of hip-hop star and high Gypsy priestess. On this day she was wearing a tracksuit and hefty chain from which dangled a slab of agate bordered in gems. Tiny diamonds glistened in her teeth, and a half-dozen jeweled tennis bracelets encircled her wrists, each, for the artist, an individual badge of success.

Sprinkled with phrases too salty for a family news organization, Ms. Longshore’s conversation is a performance in itself. “Look I’m standing here in front of you right now with my thighs touching,” she said. “My Spanx are squeezing me. I got myself a hug going on there. I’m feeling good.”

She may have had another reason. On this afternoon she sold five or six canvases, she said, adding that this was a typical haul, taking in a total of $65,000. Her patrons are an odd assortment of actors, well-heeled matrons, hedge-fund managers and scores of more modest believers in Ms. Longshore’s gospel.

“This is America,” she likes to preach. “Here, if you’re willing to work hard enough, you can look at yourself every morning, pinch your nipples and smile, and say goddamn it, ‘I can go out and do anything I need to do.’”

Often bearing cartoonlike images of accomplished, much- mythologized females — Ms. Wintour, Frida Kahlo and Audrey Hepburn among them — Ms. Longshore’s canvases are intended as testaments to female empowerment. “‘When you want a helping hand, look at the end of your arm,’” Ms. Longshore likes to say, quoting Ms. Hepburn, a longtime idol.

Ms. Longshore’s long workdays and social-media presence (she sells 35 to 40 percent of her work on Instagram, she said) have led her to associations with a wide range of brands including Chloé, Anthropologie, Shiseido and Mark Cross. She won’t stop there if she can help it. “Oh, Alessandro, Alessandro,” she yodeled, a shameless cue for Alessandro Michele, the Gucci creative director.

Ms. Longshore has deliberately bypassed the gallery circuit. “I’m not just an artist, I’m an entrepreneur,” she said. “I want to represent myself. I want to keep 100 percent of my profit margin.”

At Bergdorf, she said, “I’m curating them and they’re curating me.” Not every item in her raunchy oeuvre would likely make the cut.

Defining ‘Ambitcheous’

Conventional dealers may well look askance at her work, some dismissing it as tasteless or garish. “It is art that certainly could polarize,” Mr. Bamberger acknowledged. But these days, he said, “when you buy a work of art, you buy into the person, the whole package, and Instagram is where the whole package plays out.”

It doesn’t hurt, either, that Ms. Longshore is relentlessly upbeat, “The word ‘don’t’ doesn’t enter her vocabulary,” Mr. Bamberger said.

It wasn’t always so. In Montgomery, Ala., where she grew up, “I was this weird kid who got picked on because I had a big voice and a loud personality,” Ms. Longshore recalled. But her mother had dreams for her, imagining Ashley at cotillion, fanning out her party dress and batting her eyes at the eligible boys.

“I was raised by the garden club, and my underwear had a monogram on it until I started my period,” Ms. Longshore said. “It would’ve been easier,” she writes in her memoir, “to dress pretty, fawn over those big-eared boys and learn my dance steps, but I couldn’t do it.”

She eventually decamped for Montana, where she taught herself to paint, and later New Orleans, a city she loves for its rawness. She peddled her earliest paintings — masturbating couples and the ribald like, to local galleries, and was mostly met with rejection. At night she sobbed, “crying snot bubbles,” she said. “I was let down by just being disrespected.”

Her tendency to go public with her triumphs and travails proved attractive. “People love all that blood, sweat and tears,” she said. Brands seem O.K. with it, too. For the Judith Leiber company Ms. Longshore created a 20-piece collection of sparkly rainbow-colored evening bags. They sold out within 13 hours of being featured on Instagram, at $6,500 apiece. “Now that’s a lot of cheese,” Ms. Longshore said.

Scores of artist-luxury brand collaborations — Jeff Koons and Louis Vuitton, Versace and Andy Warhol — have coursed through the marketplace. Art and retail collaborations date back at least to the middle of the 20th century, said Bonnie Clearwater, the director and chief curator of the NSU Museum of Art in Fort Lauderdale, Fla, noting that in the 1940s Mark Rothko displayed his canvases at Macy’s.

Bergdorf entered the fray more recently. Last year, at its inaugural exhibitions, the store sold some work priced in the mid-five figures. “I found it interesting that we could sell art at that price point,” said Andrew Mandell, the vice president and divisional merchandise manager of the store’s home division.

Ms. Longshore’s installation, besides burnishing her credentials, was expected to boost traffic on the store’s customarily sedate home goods floor, Mr. Mandell said. “We believe we are engaging new customers,” he said. “Ashley has a mature audience buying her pricier works. But she has more millennials, I would assume, than we do.”

Showcasing artists in a retail environment is one way to draw online shoppers back to stores, suggested Roma Cohen, who sells upscale street wear at Alchemist, his concept store in Miami Beach. Mr. Cohen, who has initiated collaborations with Damien Hirst, Marina Abramovic and their influential like, and whose own fashion/music/art installation is on view at Bergdorf this week, added, “People like to feel they are getting an experience,” one that they’re inclined to photograph and share.

Ms. Longshore is well ahead of that game. On her social media platforms she exposes not just her art but her own perceived flaws: runaway carb cravings, a tendency to hoard and an unyielding competitive drive. She’s “ambitcheous,” Ms. Longshore acknowledged. Sorry, not sorry. “I’m brave enough to be who I am in a society where there’s a lot of pressure to be perfect,” she said.

There is no danger that she will succumb. An edge of defiance creeping into her voice, she recalled having dealt with overbearing Masters of the Universe. “When I get these hedge-fund guys in here, I know how to talk to them,” she said. “I’m not sitting here batting my eyes and smiling. I’m not about to be ground down.”

She has encountered her share of mean girls too. “But I’ve learned my lesson,” Ms. Longshore said. She turned a wily glance toward her visitor. “You ain’t sitting at their damn store, are you?” she said.