American painter who painted in several abstract styles and influenced the Minimalist artists of the 1960s.

Reinhardt studied at Columbia University (1931–35) under the art historian Meyer Schapiro, and after graduation he studied at the National Academy of Design and the American Artists' School (1936–37). He was a member of the American Abstract Artists group from 1937 to 1947 and had his first one-man show in 1943 in New York City. He subsequently taught at various colleges. Reinhardt's paintings from the 1930s exhibit brightly coloured, hard-edged geometric designs influenced by Cubism and the Dutch painter Piet Mondrian. In the 1940s he adopted a softer style using rectilinear patterns of small abstract elements evenly distributed over the canvas. By the early 1950s Reinhardt had restricted his works to monochrome paintings—at first red and later blue—incorporating symmetrically placed squares and oblong shapes against backgrounds of similar colour. His later paintings consist of large interlocking rectangles painted in variations of black.

Reinhardt influenced the course of painting more through his activities as a polemicist than as a painter. He explained his own stylistic evolution in dogmatic and conceptual terms as a conscious search for an art that would be entirely separate from life. In his case this took the form of nearly monochrome canvases in which drawing, line, brushwork, texture, light, and most other visual elements were suppressed. The impersonality and exactitude of his works presaged those of the Minimalist painters. With Robert Motherwell, Reinhardt coedited Modern Artists in America (1950). Art-as-Art: The Selected Writings of Ad Reinhardt was published in 1975.