LOS ANGELES, CA.- When Ann Philbin was asked by a Los Angeles artist if she would consider leaving the Drawing Center in New York in the late 1990s to run the Hammer Museum here, she demurred. She had never even heard of the Hammer Museum.

And when, at the urging of the artist, Lari Pittman, she agreed to at least visit the museum while on a West Coast trip in 1998, her heart sank at the sight of the pink marble lobby in the Occidental Petroleum Building that led to the adjoining museum that Occidental’s founder, Armand Hammer, had built eight years earlier to display his collection of old masters and other paintings.

“I’m a contemporary art person, and I love architecture and design, so the place kind of hurt my eyes,” Philbin recalled.

But now, 24 years after Philbin agreed to sign on as the museum’s director for what she had once thought would be a five-year stint in Los Angeles, the Hammer is finally concluding a $90 million stop-and-start renovation project with the opening of a prominent entrance that integrates the museum onto the streetscape of Wilshire Boulevard, one of the city’s main thoroughfares.

With this final chapter of the renovation, the days of walking into the Hammer from an underground parking lot beneath the Occidental Petroleum Building, or a small entrance on a Westwood side street — not exactly the Louvre pyramid or the grand steps on Fifth Avenue to the Metropolitan Museum of Art — are over.

“You would literally drive by it and be like, isn’t that a petroleum office building?” artist Mark Bradford recalled.

An opening party Saturday night for museum members will feature DJ Pee .Wee (Anderson .Paak), and a series of events for the public has been planned for Sunday.

The renovation — part of a building boom that is transforming the vibrant Los Angeles museum world — caps the Hammer’s emergence as one of the more influential museums in the country, and one that is now known for its promotion of contemporary and up-and-coming artists.

It is the latest sign of how Philbin, who commissioned the project soon after she arrived here (“I could see what it could be,” she said), has dramatically remade the museum both inside and out, in the process turning it into a powerful force in the contemporary art world in LA and beyond.

“She took what was a very respected regional museum and put it on the national stage,” said Lisa Phillips, director of the New Museum in New York. “It really hadn’t been there before her arrival.”

The transformation of the Hammer goes well beyond the physical building. Since Philbin took over in 1999, the Hammer’s annual budget has increased from $6 million to $28 million, while the size of its staff has gone from 35 to 100 full-time employees. Its endowment increased from $35 million to over $125 million. And it has collected more than 4,000 pieces of contemporary art over that time, significantly reorienting the focus of a museum that had none when she arrived.

The museum will mark this moment with an exhibition drawn from its contemporary collection, presented in galleries that have until now primarily been used for temporary exhibits. Among the 100 pieces that will be put on display will be the work of established and emerging artists, including Bradford, Robert Gober, Njideka Akunyili Crosby, Nicole Eisenman, Eva Hesse and Laura Owens.

The renovated space is a far cry from the somewhat stuffy repository that architect Edward Larrabee Barnes, in one of his last major projects, designed to house Hammer’s prized collection of impressionist paintings and European artworks dating back to the Renaissance. The three-story museum was built in 1990, tacked on to Occidental’s 15-floor headquarters.

“It felt like a very sleepy corporate office,” said Michael Maltzan, whom Philbin hired as the architect in 2000. “Like tumbleweeds blowing across it. Armand Hammer was at the end of his life when the museum opened, and they had rushed to get the building done. So it felt like a kind of slightly unfinished project.”

Hammer died in December 1990, just weeks after the museum opened to the public, leaving his new museum mired in disputes and facing an uncertain future. The University of California, Los Angeles, took over its management and operation in 1994. Five years later, Philbin signed on and turned to remaking the space.

“For Hammer, it was more of a vanity project to display his artwork, but for a museum to really have longer-term impact on the community, it has to be a living organism,” said Zev Yaroslavsky, who as a member of the Los Angeles City Council helped Hammer win approval for the project, and who now teaches at the Luskin School of Public Affairs at UCLA.

“Annie and UCLA have ensured that this is a 21st-century space, not just a 1980s space.”

This was a methodical renovation, reflecting the constraints of the building’s footprint (no going up or out, Maltzan said) and the pace of fundraising.

Over the course of more than two decades, what once was 16,600 square feet of gallery space has ballooned to 26,600, including a new outdoor sculpture terrace on Wilshire Boulevard. The gallery ceilings have been raised, and the ornate molding that framed the rooms holding Armand Hammer’s collection — which includes works by Vincent van Gogh, Paul Gauguin, Claude Monet, Henri de Toulouse-Lautrec and Rembrandt — is gone.

“She took the most boring space and made it a space of imagination for artists,” Bradford said. (Philbin said that before the renovation, one young artist had resisted her entreaties to show his work there, complaining about the fussiness of the Hammer galleries. “A knife in my heart,” she said, though she could not disagree.)

An outdoor courtyard at the center of the museum teems most days with museumgoers, students from UCLA and others who wandered off the streets of Westwood. (Admission to the museum is free.) Lulu, the inside-outside restaurant by Alice Waters and David Tanis that opened there in 2021, is also a draw; actor Frances McDormand was spotted eating lunch there one recent afternoon.

The new entrance on the west end of the building — now called, in recognition of a $30 million donation to the project, the Lynda and Stewart Resnick Cultural Center — is across from a planned subway stop on the city’s new Purple Line, part of an ongoing $40 billion expansion of its mass transit system. An outdoor sculpture terrace is now home to a 25-foot bronze statue by Los Angeles-born artist Sanford Biggers, originally commissioned by the Rockefeller Center and on long-term loan to the Hammer.

Inside the refurbished lobby the other day, workers were finishing the installation of an intricate, floor-to-ceiling red wool temporary sculpture called The Network, by Japanese artist Chiharu Shiota.

Maltzan said he was guided by the idea of making the building more transparent — doors have been widened and new windows installed, overlooking the street — and thus more inviting.

Still, he said, when he took the commission, he was daunted at the idea of redoing a building that had been designed by someone of Barnes’ stature.

“I was freaked; I was messing around with this extremely well-known architect,” he said.

Maltzan flew to meet with Barnes at his home in Cambridge, Massachusetts.

“He said, ‘You should feel completely free to do whatever you need to do,’” Maltzan said.

Pittman, a longtime art professor at UCLA whose work has been displayed at the Hammer, said he had asked Philbin to consider leaving New York in the 1990s because of his concern about the state of the museum.

“The building was dark, dirty, dead,” he said. “No one thought of going there.”

Now, “it’s a world-class museum,” Pittman said. “It’s not an enormous museum. But it is a world-class museum.”

This project has defined Philbin’s years at the Hammer, and now that it is approaching its conclusion, some of her friends and artists who have worked with her wonder if Philbin’s tenure at the Hammer is coming to an end. But retirement is one topic (along with her age) that Philbin will not discuss.

“I will not answer the swan song question right now,” she said over lunch at Lulu.

“I will say I feel like we have achieved something really important and lasting for this institution, and I’m proud,” she said, adding: “I think if I had known it was going to take 20 years and cost $90 million, I would have thought, ‘No, I’m not up for this.’ But you know how those things go.”

This article originally appeared in The New York Times.