New York City - Only one artwork hangs in Jasper Johns’s all-white Caribbean home in St. Martin. It’s a nearly nine-foot-tall canvas in three sections: a harlequin pattern that cascades down on the right, a series of colored circles on the left, and a montage of gray encaustic brush strokes in the center. Two overlapping wooden slats are attached to the painting. To hear it from curators, gray is not just a familiar color for Mr. Johns but the essence of a long metaphysical journey, an exploration of “the condition of gray itself.” At least that’s the premise of a sprawling exhibition of his work that opens Tuesday at the Metropolitan Museum of Art in New York.

Completed in 2005, the work, “Bushbaby,” encapsulates many of Mr. Johns’s familiar themes. There’s the encaustic, an ancient technique in which pigment is suspended in wax, giving each brush stroke a distinct materiality; the harlequin pattern, a nod to early Modern masters like Cézanne and Picasso; the strips of wood, introducing a three-dimensional element to an otherwise flat canvas; a string hanging from one slat, a suggestion of movement; and the color gray, which Mr. Johns has explored off and on throughout his nearly six-decade career.

But when pressed on the show’s focus, he said simply: “Yes, gray has been important to me. But I don’t tend to think of it as separate from the rest of my work.”

The response is classic Johns. In a parallel to his mysterious grays, suggesting both effacement and a resolute ambiguity, Mr. Johns seems to have perfected the art of talking about his work without ever revealing too much. Always courtly, he answers questions in a measured, seemingly straightforward manner that leaves a listener wanting to know far more. It’s as if he is aware that a myth surrounds him that he must be careful not to dispel.

For decades now his interpretation of flags and targets, numbers and letters — things, as he has often said, “the mind already knows,” “things that were seen and not looked at, not examined” — have become as embedded in the contemporary American art psyche as Andy Warhol’s soup cans or Jackson Pollock’s drips.

Yet until this exhibition was organized, his use of gray — as a pigment, a stenciled word, a section of crosshatching — had not been singled out for sustained attention. The show, which began at the Art Institute of Chicago, insists that attention must finally be paid to what Mr. Johns once said was his “favorite color.”

Although monochrome paintings have existed throughout history, Mr. Johns said he wasn’t trying to be part of any tradition. “I was trying to do something else.”

Throughout this career he has relentlessly pushed his work to new places, from the flags of the 1950s to the maps of the ’60s to the “Seasons” cycle of the ’80s, in which he seems to appear as a vulnerable phantom figure. His explorations, in which the literal and conceptual can overlap in provocative ways, have served as inspirations to younger artists.

“Without question he’s one of the most important painters of his generation,” said Robert Storr, who is the dean of Yale University’s School of Art and has known Mr. Johns since the late 1960s. “He put bits and pieces of painting and conceptual practice together in a way that nobody has done.”  

In 1980 the Whitney Museum of American Art spent $1 million for “Three Flags,” then the highest price ever paid for the work of a living artist. In 1988 his painting “False Start” (1959) brought $17 million at an auction at Sotheby’s. In 2006 the Hollywood mogul David Geffen sold “False Start” to the Chicago hedge-fund manager Kenneth C. Griffin for $80 million.

“False Start” thus holds the title of most expensive painting by a living artist and is a star in the Met’s show. A riot of blues, reds and oranges with stenciled letters spelling out the names of colors (including gray), it plays neatly off the exhibition’s premise — it has a grisaille counterpart in the show, “Jubilee” — and harks back to Mr. Johns’s storied collaboration with Mr. Rauschenberg in the 1950s.

He studied briefly at the University of South Carolina before coming in the late 1940s to New York, where he supported himself working odd jobs. It was there that he met the composer John Cage, Mr. Cunningham and Mr. Rauschenberg. Mr. Rauschenberg in turn introduced Mr. Johns to the dealer Leo Castelli, who gave him his first one-man show in 1958.

He first began visiting St. Martin in the late 1960s and bought the property here in 1972. The architect Philip Johnson is the principal designer of his home, a long, white, rectangular structure divided into three distinct sections. There is a 40-foot living room, dining area and kitchen; a bedroom; and his studio. Sliding glass doors span the entire length of both sides of the building. On one side they open onto a terrace overlooking the lagoon and Marigot Bay; on the other are views of the swimming pool and pavilion.

This has been an unusual winter for Mr. Johns. For one thing, he has been preoccupied with the “Gray” show and with a large exhibition of drawings that opened on Friday at the Matthew Marks Gallery in Chelsea. “These shows bring you into a different frame of mind because you’re having to think a lot about things that you have already done rather than about what you’re doing,” he said.

It was crucial to Mr. Johns that “Gray” include not just his paintings but also prints, drawings and sculptures. He often executes drawings after he finishes a canvas, rather than before. “To do a drawing for a painting most often means doing something very sketchy and schematic and then later making it polished,” he said. “It’s done out of a different kind of energy. I love drawings, so I’ve always enjoyed making drawings that exist on their own.”

Yet the idea for the “Gray” show originated when Mr. Johns departed from that norm, producing a predominantly gray untitled drawing in 2001 that paved the way for a large 2002 painting.

So he and James Wood, then the museum’s director, visited St. Martin to view the painting, “Near the Lagoon,” which measures nearly 10 by 7 feet and, like the drawing, was inspired by Manet’s “Execution of Maximilian” from 1867-68. The Art Institute ended up buying the painting.

For Nan Rosenthal, one of the curators of the Met show, it was crucial that the museum take an in-depth look at Mr. Johns’s career. (The Met acquired its first Johns painting, “White Flag” from 1955, only a decade ago.) “A show as luscious and challenging as Jasper’s gray works definitely belongs here,” Ms. Rosenthal said.

Some of the drawings at Matthew Marks — all of which date from the past 10 years — correspond to paintings in the Met’s show. Among them is “Within,” a 2007 drawing with a predominantly gray background and Mr. Johns’s signature crosshatched imagery, over which he has painted a flagstone-like motif. It was inspired by a painting he started in 1983 and did not finish until 2005.

By . . . Carol Vogel