Fit has been at the core of Chamberlain’s method and aesthetic from the beginning, and his works in all mediums reflect it. He describes it as a kind of handshake, a natural balance—and, in the case of sculpture, compression—of forms that is never forced, as though preordained by the material itself. Donna De Salvo, the chief curator at New York’s Whitney Museum of American Art, calls this “controlled chance.” The pieces are welded only to hold them together so they can be moved, not as a principle of their construction. “I once made a piece that fit so well it had 47 parts without a single weld, but I had to destroy it because it couldn’t be moved,” the artist recalls.

The son of a fifth-generation saloon keeper, Chamberlain was born in 1927 in Rochester, Indiana, and as a child wanted a career in aeronautics. A series of awakenings threw him in a different direction. One occurred when he was 11, upon hearing Schubert; another came after his navy service in World War II when he saw his first van Gogh, at the Art Institute of Chicago, where he was studying on the GI Bill. “I thought Schubert and van Gogh were impeccable—you couldn’t add or take away one note or one brushstroke,” he says.

Thus were sown the seeds of a perfect fit, although it would take 10 years of odd jobs, such as hairdressing, before they flowered into sculpture. “I started in 1948, and the next years were my apprenticeship, finding out what I didn’t want to do,” Chamberlain says. “I had to discover that I like fitting things together, rather than modeling or chipping away at something.”

He had another breakthrough in 1955–56, when he attended Black Mountain College, the fabled North Carolina experiment in arts education. “The place was run by the poets,” he recalls. He was particularly impressed by the way Charles Olsen and Robert Creeley, two of the teachers there, put words together—another form of fit. The college closed in 1957, and everyone went to New York.

Chamberlain’s early sculptural works, such as Calliope, 1954, were influenced by David Smith, but he liked the gestural and muscular style of Willem de Kooning and Franz Kline, both of whom were regulars at the Cedar Tavern, the famous artists’ hangout in Greenwich Village. Chamberlain would sit and talk with them at the Cedar, waiting for someone to finish a pack of cigarettes so he could wad it up to see what it would look like. In 2001 Pace exhibited several de Koonings and Chamberlains side by side, revealing how such works as the painter’s Flowers, Mary’s Table, 1971, and the sculptor’s Miss Lucy Pink, 1963, with its colored planes and volumes, vibrate with uncannily similar synergy.

Chamberlain travels and goes to exhibitions “if sedated and dragged.” He recently saw the Cai Guo-Qiang show “I Want to Believe,” at the Guggenheim Museum in New York and was very taken with the 1998 Borrowing Your Enemy’s Arrows, a huge boat bristling with 3,000 arrows. He says he “liked the ingenuity of the kid in the battle who collected the arrows.” But he feels distant from the work: “Like a lot of art you see, it’s a lot of effort to little effect.”

His own sculpture has appeared at the Guggenheim and in many other museums and galleries; he has had more than 200 solo shows. “One of the characteristics of my stuff is that you can walk around it, and it changes,” Chamberlain says, noting that his sculptures have no front or back or single “best” profile.

Sculpture began to sell well about 10 years ago, but 2004, according to Pace, was a tipping point for Chamberlain, who made only 18-inch-high “baby tycoons” that year because he had had back surgery. At first they were priced at $17,000 apiece, then $35,000, and they now go for $100,000 to $200,000. At auction in May 2007, a 1962 untitled painted and chromium-plated steel sculpture sold at Phillips de Pury in New York for $1.38 million—$900,000 above the high estimate and an artist’s record. Chamberlain doesn’t talk much about money or arrangements (“Ask my wife”), but he knows where he stands in the world. He has several dealers in the U.S. and Europe—Anthony Meier Fine Arts, in San Francisco, and Karsten Greve, in Paris and Cologne, among them—who buy his work upfront. His next show, featuring a new life-size piece, Rosetuxedo, is scheduled to open in October at KN Gallery, in Chicago. Priced in the low seven figures, Rosetuxedo is the first work Chamberlain has had fabricated for him. After 60 years of making art, he is still most interested in discovery—a new technique, a new shape, a new material. As he puts it: “The key activity of art is to find out what you don’t know.”