The man with the gavel for Sotheby’s $1 billion week

He knew which clients were interested in the painting, where their advisers were sitting and who was fielding bids from the phones lining the saleroom.

From the rostrum, Barker leaned in dramatically, smiled, sometimes waited. After an electric 20-minute bidding war, Barker brought his hammer down to an eruption of applause. Gustav Klimt’s “Portrait of Elisabeth Lederer" went for $236.4 million, becoming the world’s most expensive modern artwork ever sold at auction.

Two days later, Barker presided over the sale of Frida Kahlo’s 1940 canvas, “The Dream (The Bed)," for $54.7 million, setting a record for a woman artist at auction. Barker, chairman of Sotheby’s Europe and its principal auctioneer, had meticulously prepared for what turned out to be a banner week for the auction house, with more than $1.1 billion of art sold as of Thursday.

“I don’t like to leave things to chance and stand up there and just let things happen," said Barker, 54. “It’s a very choreographed and deliberate process."

The Tuesday evening sale of two dozen pieces from cosmetics executive Leonard Lauder’s estate was the first auction in Sotheby’s new home in New York’s modernist Breuer building, where Lauder had once served as chairman of the Whitney Museum of American Art. All the Lauder pieces sold, including the Klimt, an Edvard Munch painting and Henri Matisse bronzes, for $528 million combined.

Barker, who has worked at Sotheby’s for more than three decades—his entire career—flew from London to New York to oversee the series of high-profile auctions during one of the busiest art months of the year on this side of the Atlantic.

The Klimt auction was like watching a tennis match, said Mari-Claudia Jiménez, Sotheby’s former chairman and president, who worked with Barker for nearly a decade. Jiménez, now working in art law, was at the auction Tuesday night.

“Every second, every volley, your head is swiveling from side to side," she said. Barker is like a 6-foot-4-inch dancer at the rostrum, and he gives people time to deliberate, she said.

Every generation has their auctioneer. This one, she said, has “Olly."

“When I started working with Olly, he was already famous," Jiménez said. “When I ended, he was really famous."

Barker grew up in London, making frequent visits to the Tate museum. His mother worked in advertising. His father was an accountant until the company where he worked went under on Black Monday, the stock market crash of 1987, and then went into the restaurant business.

“Believe it or not, I was incredibly shy," he said, recounting his fear at having to recite poetry in school. “At the same time, I enjoyed it. I kind of loved the scariness. It’s like stepping out on the wire—once you step out, there’s no going back."

He studied art history, first as an undergraduate at Manchester University, then as a graduate student at the Courtauld Institute of Art, an independent college of the University of London.

He joined Sotheby’s as an intern in October 1993. He spent the better part of a decade in the impressionist and modern-art department before moving to work under Tobias Meyer, then Sotheby’s worldwide head of contemporary art and principal auctioneer.

One of Barker’s first auctions was a Middle Eastern travel and map sale. He says he was “a complete disaster," struggling to read the rhythm of the room.

Barker eventually succeeded Meyer as principal auctioneer and has presided over milestone sales for the art world, as well as some of its most viral cultural moments.

Barker was looking out the window of a London bus in 2003 when he noticed that Pharmacy, a restaurant hot spot opened by British artist Damien Hirst and public-relations executive Matthew Freud, had closed. Its contents would make for a fantastic auction, he thought.

The following year, Barker staged the auction of everything inside the chemist-themed restaurant—butterfly paintings, glass vial salt and pepper shakers, and aspirin-shaped bar stools—all made by Hirst. Its success became Barker’s early calling card.

Barker later suggested the idea of a direct-to-auction sale of new works by Hirst, bypassing the artist’s dealers. The 2008 auction included more than 200 works by Hirst, from animals in formaldehyde tanks to polka-dot-covered canvases. The two-day auction, which started the same day that Lehman Brothers collapsed, brought in roughly $200 million, setting a record for a single-artist auction.

“If that sale had been maybe 24 hours later, I think it could have been a very different and potentially deflationary result," Barker said.

Barker says he is superstitious and has fine-tuned his routine to prepare for an auction. In addition to a session with a massage therapist, he sometimes rides his Peloton. The compression socks were a tip from Meyer, who had gotten the idea from a brain-surgeon friend, to help with stamina when he’s on his feet for sessions that can last up to five hours. He sometimes wears a special pair of Berluti dress shoes—“a lucky charm"— that Meyer insisted on buying for Barker before a Hirst sale.

He always uses a wooden gavel, now chipped, that his father gave him roughly 25 years ago before he died. It’s “my kind of chosen lightsaber," Barker said. “There have been a couple of times when I thought I’d lost it. If I ever did, it really would be a big problem for me."

In 2018, immediately after Barker brought the hammer down on the sale of British street artist Banksy’s “Girl With Balloon" for $1.4 million, everyone in the room was shocked when the stenciled painting began to pass through a shredder hidden in the bottom of the frame, leaving the bottom half in thin, dangling strips. Sotheby’s said it was just as stunned as everyone else. Banksy soon took credit for the prank, saying he hid the remote-controlled shredder in the frame.

It worked out well for the buyer, who opted to still acquire the piece. Three years later, Barker auctioned the half-shredded painting for $25.4 million. “I can’t tell you how nervous I am to drop the gavel on this one," Barker said in the moment.

Barker’s international profile got a boost when he conducted Sotheby’s first livestreamed, online auction in June 2020 during the Covid-19 pandemic. “Sotheby’s or Christie’s were sort of a closed theater up until that point. It was like going to Broadway," Barker said. “Suddenly, with Covid, we became Netflix."

And Barker was the on-screen entertainment.

Even without the adrenaline of a packed room, he drummed up a bidding war and ultimately sold Francis Bacon’s “Triptych Inspired by the Oresteia of Aeschylus" for $85 million. The buyer was later revealed to be Sotheby’s new owner, telecom billionaire Patrick Drahi.

Barker wore a Spencer Hart tuxedo jacket to Tuesday evening’s auction, but he was back in his usual suit on Thursday. There was a buzz in the room as he stood before Mexican painter Kahlo’s sleeping self-portrait. After roughly five minutes of dogged competition between a pair of telephone bidders, it sold for $54.7 million. All in, Barker had personally auctioned $735 million of art in one week.

“Miraculous things can happen in the auction," Barker said before the historic Kahlo sale. “My role is to make that happen."

Write to Francesca Fontana at francesca.fontana@wsj.com