American sculptor whose pioneering welded metal sculpture and massive painted geometric forms made him the most original American sculptor in the decades after World War II. His work greatly influenced the brightly coloured “primary structures” of Minimal (minimalism) art during the 1960s.

Smith was never trained as a sculptor, but he learned to work with metal in 1925, when he was briefly employed as a riveter at the Studebaker automobile plant in South Bend, Indiana. Dropping out of college after his first year, he moved to New York City and, while working variously as a taxi driver, salesman, and carpenter, studied painting under John Sloan and the Czech abstract painter Jan Matulka.

Smith's sculpture grew out of his early abstract paintings of urban scenes, which were reminiscent of the work of his friend Stuart Davis. Experimenting with texture, he began to attach bits of wood, metal strips, and found objects to his paintings, until the canvases were reduced to virtual bases supporting sculptural superstructures. Long after he stopped painting, his sculpture continued to betray its pictorial origins: his overriding concern with the interplay of two-dimensional planes and the articulation of their surfaces led Smith to abrade or to paint his sculpture while often ignoring the traditional sculptural problems of developing forms in three-dimensional space.

Smith's interest in freestanding sculpture dates from the early 1930s, when he first saw illustrations of the welded metal sculpture of Pablo Picasso and another Spanish sculptor, Julio González (González, Julio). Following their example, Smith became the first American artist to make welded metal sculpture. He found a creative freedom in this technique that, combined with the liberating influence of the Surrealist (Surrealism) doctrine that art springs from the spontaneous expression of the unconscious mind, allowed him soon to produce a large body of abstract biomorphic forms remarkable for their erratic inventiveness, their stylistic diversity, and their high aesthetic quality.

In 1940 Smith moved to Bolton Landing, New York, where he made sculpture during World War II when not assembling locomotives and tanks in a defense plant. For a time after the war, he continued to work in a bewildering profusion of styles, but toward the end of the decade he disciplined his exuberant imagination by making pieces in stylistically unified series. Such series of sculptures were often continued over a period of years concurrently with other series of radically different styles. With the Albany series (begun in 1959) and the Zig series the following year, Smith's work became more geometric and monumental. In Zigs, his most successful Cubist works, he used paint to emphasize the relationships of planes, but in his Cubi (begun in 1963), his last great series, Smith relied instead on the light of the sculptures' outdoor surroundings to bring their burnished stainless-steel surfaces to life. These pieces abandon two-dimensional planes for cylinders and rectilinear solids that achieve a sense of massive volume. Smith joined these cubiform elements at odd and seemingly haphazard angles, in dynamically unstable arrangements that communicate an effect of weightlessness and freedom.