NEW YORK—Laura Paulson, a senior director of post-war art at Christie’s New York, remembers precisely when the market for Christopher Wool’s paintings shifted into a new pricing category. It was May 19, 1999, and Christie’s was offering the artist’s black-and-white word painting Untitled (FOOL) (1990), with an estimate of $40,000 to $60,000. But the bidding was furious, driving the final price up to $420,500.

“FOOL was a definite sign that his paintings were starting to have a life of their own,” says Paulson, who was with Luhring Augustine in New York from 1985—when the gallery first began representing Wool—to 1989. At the time of the sale, some wondered whether the winning bidder, New York art adviser Thea Westreich, was herself a fool for paying such a price for a Wool. But Westreich, who reportedly won the piece for New York collectors Melissa and Robert Soros, says, “It was a steal.”

And now that Wool’s prices have passed the $1 million mark, anything under $500,000 looks like a bargain. At Sotheby’s New York this past May, the artist’s auction record was set when L&M Arts of New York bought Untitled (1988), for $1.4 million.

To Paulson and many other market observers, the dramatic climb of Wool’s auction sales is a clear sign that he has entered the ranks of 1980s artists who have been anointed by the marketplace as the “must-haves” of their era. “First there was Cindy Sherman, then Robert Gober, then Jeff Koons; now it’s Christopher Wool,” says Westreich, who for 23 years has been visiting the artist’s studio with collectors.

Wool was born in Chicago in 1955 and currently lives and works in New York. He had his first exhibition at White Columns in New York in 1982 and has had a consistent international gallery presence ever since. His work, which often refers to mass culture and the popular media, utilizes conceptual strategies and draws from both Minimalism and Pop art.

As Westreich explains, he borrows from the stripped-down approach of Donald Judd or Dan Flavin and infuses their spare forms with a Duchampian or Warholian sense of humor. He has used a range of techniques, including silkscreen, photography and paint, which he applies using rollers and stencils.

Wool tends to explore a single formal approach or idea for a couple of years before moving on to another. He does, however, often return to the same images later, or explore similar iconography from a different perspective or with a different technique. He’s been quoted as saying that he’s more interested in how to paint than what to paint.

In 1985-86, for example, he was working with drip paintings, somewhat inspired by Jackson Pollock, on steel backed by wood, and then began to use a rubber roller to apply “wallpaper” patterns—dots, vines, flowers or clover leafs—in shiny black enamel. A couple of years later, he switched to using rubber stamps, replicating a single image like a flower or a bird in alkyd on paper.

In the 1990s Wool made his first silkscreens of large blown-up flowers, recycling some of the iconography of the wallpaper images and the stamp pictures, and also embarked on a series of paintings of entwined loops, reminiscent of Cy Twombly’s blackboard paintings.

A range of his output—some 40 works—was on view earlier this year in a major exhibition that opened at the Institut Valencià de Art Modern (Spain), and then traveled to the Musée d’Art Moderne et Contemporain in Strasbourg, France. His latest body of work, on view at Simon Lee Gallery in London through Nov. 28, employs silkscreen and black enamel spray paint that is meticulously built up on the surface and then partially removed. These paintings are priced from $50,000 to $185,000.

Westreich believes Wool has finally received the attention he deserves, and the market has begun to reflect that, as a handful of collectors with deep pockets are aggressively seeking out his work. “The Peter Brants, along with dealers such as Larry Gagosian, Perry Rubenstein and Per Skarstedt, have driven prices up, paying mightily for works that only a few years ago could be acquired for $60,000 to $80,000 on the primary market,” she says. Brant reportedly paid more than $2 million for a Wool text painting on the private market, which “sparked considerable interest throughout the art world and appropriately reflects the importance of the work,” says Westreich.