I first met Eva Chow — encountered would actually be a better term — in 2013 in the courtyard of the Los Angeles County Museum of Art. It was the museum’s third Art & Film Gala, and Mrs. Chow, a host with Leonardo DiCaprio, was working the room like a piranha in a goldfish bowl. Air kisses with Fran-Henri Pinault. Chitchat with Jane Fonda. An excited wave to Ed Ruscha.

After elbowing to her jet-embroidered side (she was wearing a black column gown, custom made by Gucci), I reached out to shake her hand and introduce myself. Instead of grasping it, the cultural queen handed me a Champagne flute. “Could you hold this for a minute?” she said, before I got a word out. Photographers descended.

Flash! Pop! And then she was gone.

For the last 23 years, Mrs. Chow — first name pronounced Aay-vah, obviously — has been largely defined by her marriage to Michael Chow, the celebrity restaurateur. She gave up a successful fashion line, Eva Chun, in 1994 to be a mother. Yes, she has played a crucial role in keeping the Mr. Chow chain humming. But mostly her husband has basked in the spotlight while she has played the supporting part.

That seems to be changing. With the bespectacled Mr. Chow approaching 77 and concentrating on making art, Mrs. Chow, who is in her late 50s, has increased her focus on their business, particularly when it comes to growth. A sixth location opened in Malibu, Calif., in 2012. Las Vegas and Mexico City are next. Last month, she oversaw the introduction of an exclusive Mr. Chow-branded wine.

“I have to do more,” Mrs. Chow said over tea at her mansion here two weeks ago. “Michael paints day and night, and I mean day and night obsessively.”

Mrs. Chow has also become perhaps the most high-profile member of the board of the Los Angeles County Museum of Art, no small feat considering that the 53-member board includes the likes of Elaine Wynn, Casey Wasserman and Lynda Resnick. Starting in 2011, Mrs. Chow began a new effort to raise money for film-related programming. Her resulting Art & Film Gala, sponsored by Gucci and held next on Nov. 7, has since been deemed a West Coast version of Anna Wintour’s Met Gala.

While some prominent Angelenos grit their teeth over Mrs. Chow’s subtly unsubtle style (one cited an article that called her “a formidable perfumed steamroller of a woman”), even the unconverted concede that she probably reigns as the city’s top hostess. Last year, she regaled President Obama and Kanye West — at the same time — in the family’s Macassar-ebony-lined library. “She throws the most glamorous parties in all of L.A.,” Inez van Lamsweerde and Vinoodh Matadin, the fashion photographers, wrote in an email.

With her stature rising and the next Art & Film Gala on the horizon, I wanted to know more about this apparent goddess. So the Los Angeles County Museum of Art helped arrange an afternoon interview for mid-October. (“You’ll love her,” Michael Govan, the museum’s director, told me. “Just don’t go too early. She likes to sleep late.”) The venue would be her 11,600-square-foot Holmby Hills estate, the one modeled after the Reina Sofía museum in Madrid.

When I arrived, the white gates swung open and an attendant in a business suit directed my oh-so-chic Chevy Malibu into the curved driveway. Before I was barely out of the car, Mrs. Chow — whom Mr. Ruscha described in an email as “a lovely, forward-motion machine” — flung open her front door and greeted me with a big smile and an offer of Champagne. It was 2:30 p.m.

“I love to have a glass or two of Champagne in the afternoon,” she said.

With her spunky Pomeranian, Baby Chow, capering about her feet, Mrs. Chow walked us through the entry hall, where paintings by Julian Schnabel and Damien Hirst are hung. We passed that fancy library. (“This is where we entertained the president,” she said, with a casual wave.) And we emerged in what she called “gold room” — gold-paneled walls, a gold folding screen, gold Jean Dunand baubles.

“I really think that Los Angeles is having a moment,” she said as we sat down. (To her seeming disappointment, I declined the Champagne; green tea was summoned from a servant instead.) “There has always been a cool energy here, but right now we’re in a period of exciting artistic growth. More and more, all spectrum of creative people are coming together.”

As she spoke in a calm, even tone, looking me squarely in the eye and her teacup held just so, she seemed nothing like the larger-than-life creature at the gala. She was wearing a simple twin set with a full black skirt and flats. She had on very little makeup and no nail polish. Her husky laugh — huh, huh, huh — was infectious.

I asked a question that seemed to startle her: After living an opulent life for more than two decades, with friends like Al Pacino and Alber Elbaz, the Lanvin creative director, and the art dealer Larry Gagosian on speed dial, did anything truly impress her anymore?

“It’s not like I get impressed once, and I’m over it, and I need something new,” she said. “I love this teacup. It impresses me. When I love something, whether things or people, I love them very deeply.”

She is the third Mrs. Chow. (Or maybe even the fourth; some magazine profiles over the years have indicated that Mr. Chow was briefly married in the 1960s. Asked to clarify, he responded: “I’m not a family lawyer, nor an accountant. I don’t think it’s relevant.”) She was preceded by the model Tina Chow, who died in 1992; and, before that, Grace Coddington, who is now the creative director at Vogue.

Eva Chun, who moved to Los Angeles from Korea in 1974, after the death of her father, a banker, met her husband at a party for Gianni Versace. “I had seen him before and was very much a fan of the restaurant,” Mrs. Chow recalled. “But it was then that he asked for my phone number.”

By that time, roughly 1991 (Michael and Tina divorced in 1990), Eva was an emerging fashion star. After arriving in California unable to speak English, she took language classes at Los Angeles City College and, on a whim, auditioned for a Dino De Laurentiis movie. She didn’t get the part, but began working for De Laurentiis as an assistant, dropping out of school. By 1981, the future Mrs. Chow had become friendly with Bo Derek, who hired her as a production manager on “Tarzan, the Ape Man.”

“When you are thrown in the water, you learn to swim,” Mrs. Chow said.

Deciding that she was more interested in fashion than film, Mrs. Chow enrolled in Otis College of Art and Design and, while still a student and working from her apartment, sent a little collection of clothes to a buyer for Neiman Marcus. Her Eva Chun line, mostly women’s evening wear heavy on silk crepe and chiffon, was soon generating annual retail sales of $2.5 million. ($4.2 million in today’s currency.)

What has made her such a lasting match for Mr. Chow?

“Who the hell knows,” said Mr. Schnabel, who has known the couple since the beginning and has painted Mrs. Chow’s portrait. “They’re both very intense. Maybe it’s because they maintain their own identities but share a sensibility.”

Mr. Chow agreed. But he also pointed to what he called his wife’s “artistic foundation,” noting that she was an apprentice painter to two major Korean artists as a young girl. “Artists do magical things, and she is an artist,” he said, adding that their Asian heritage is also important. “We were both uprooted from our countries and culture, and that meant that we immediately had a lot in common.”

Givenchy’s creative director, Riccardo Tisci, who said he has known Mrs. Chow for seven years, described her style as “very chic, very strong, sexy without being vulgar.” He added: “Not many women of that level have her flexibility. She can have serious conversations about fashion. And then you can do crazy stuff with her. When I’m in L.A., we go furniture shopping and drive around in the car with very loud music.”

Mr. Schnabel, speaking by phone from Paris, said that Mrs. Chow stands out among collectors for her “succinct, big, committed opinions: why she likes something and why she doesn’t.” He added, “Her relationship with art is not a docile one. She’s very emotional about it and talks about it like an artist.”

I found that to be true. In our interview, she spoke about fashion, noting that she loves Mr. Tisci’s designs for Givenchy (“cool and feminine but slightly edgy”), for instance, and citing Azzedine Ala愀 as an all-time favorite. Her music tastes include Beethoven and Brahms as well as Pink Floyd and Amy Winehouse, she said. Favorite films include “Reservoir Dogs” and Luchino Visconti’s “Rocco and His Brothers.”

But she seemed especially happy to talk about art, even when the conversation turned to works — say, video — that she does not collect.

“While I understand and appreciate it very much, I’m an old-fashioned kind of person in that way,” she said. “We like furnitures, we like sculptures, we like paintings. I collect china and jewelry. But as far as fine art is concerned we are very specific.”

She continued: “Art is almost like friends. You have such great friends and you don’t have enough time to spend with them. Do you really want to go and look for more friends? In some ways it’s maybe a little bit lazy of us. In some ways we are loyal and really appreciate and love the friends we have.”

Her iPhone started to ring.

“That’s probably my daughter who doesn’t have time for her mother because she’s sooo busy with school,” she said, with what looked like a roll of her eyes. She swiftly sent whomever it was to voice mail. Asia Chow, 21, is a senior at Columbia University. Mrs. Chow, who has four siblings (she’s in the middle), complained that she had managed to see Asia only once during a recent three-day trip to New York.

The entire Chow family, including China and Maximillian, Mr. Chow’s children from his marriage to Tina Chow, typically turns up for the Art & Film Gala, the next installment of which will honor James Turrell and the “Birdman” director Alejandro G. Iárritu. Mr. DiCaprio, who did not respond to an interview request, will again be a host. Tables sell for up to $100,000; full-event individual tickets are $10,000.

Some officials at rival Los Angeles museums blanch at what they suspect Mrs. Chow spends to put on the event — the budget is not public, but money seems to flow freely around her. (It certainly does at Mr. Chow, where steamed sea bass costs $45 at the Beverly Hills location.) Over the last four years, the event has raised more than $15 million, a meaningful total for the Los Angeles County Museum of Art, which has primarily used the funds to rebuild its film program.

Mr. Govan, the museum’s director, said the gala’s success is largely attributable to its cross section of attendees, especially given the surprisingly fragmented way in which the Los Angeles creative class tends to socialize.

“Eva was the one person on the board who seemed to walk easily between the film world and the art world and the fashion world and the music world,” Mr. Govan said. “I didn’t know anyone else who could do that. If we were going to have a successful film initiative, to fully recognize film as art, we had to bring the entire creative community together. And she’s done it.”