NEW YORK — Karl Benjamin, a painter who came to art almost by accident and then rose to prominence in the 1950s as part of a West Coast artists’ rebellion against the reign of Abstract Expressionism, died July 26 at his home in Claremont, Calif. He was 86.

The cause was congestive heart failure.

Mr. Benjamin, who later helped define a Southern California art scene that flourished in the 1960s with the likes of David Hockney, Judy Chicago, and John Baldessari, began his career while working as an elementary schoolteacher, gaining modest success with shows in Southern California galleries.

His canvases were known for simple, repeating geometric shapes, gridlike orderliness and fields of exuberant color that almost never bled into one another. It was a style that made him a sort of reverse Jackson Pollock, who epitomized the New York-based Abstract Expressionist school with his epic canvases of seemingly chaotic splashings and drippings.

Like many artists outside New York, Mr. Benjamin attributed his lack of a wider audience to New York’s cadre of influential critics, believing they ignored artists elsewhere.

To overcome that, he and three fellow California painters, Lorser Feitelson, Frederick Hammersley and John McLaughlin — all of them working in a cooler style of abstraction — decided in 1955 to found a movement of their own.‘‘We just knew we were not Abstract Expressionists,’’ Mr. Benjamin told an interviewer in 2006. They settled on ‘‘Abstract Classicism.’’

In 1959, the Los Angeles County Museum of Art organized a show of their work, ‘‘Four Abstract Classicists,’’ which received wide acclaim.

Critics and catalog writers renamed the group the ‘‘hard-edge’’ school, which suited Mr. Benjamin, since he was never fond of ‘‘Abstract Classicism.’’

‘‘I hate the term,’’ he told the biographers of the art historian Peter Selz in ‘‘Peter Selz: Sketches of a Life in Art.’’ ‘‘It was a sort of a merchandising idea in a sense. Something for the critics to sink their teeth into.’’

Karl Stanley Benjamin was born in Chicago and entered Northwestern University in 1943. After serving in the ­Navy during World War II, he received a degree in history at the University of Redlands in California.

He married a fellow student, Beverly Jean Paschke. To support his family he began teaching in the public schools in Bloomington, Calif., where, in addition to the three R’s, state law required him to teach art. He had not thought much about the subject before.

‘’I bought some crayons and paper,’’ he said in 2007, and the children produced drawings of trucks, trees, and mountains.

‘‘That was boring, so I said, ‘No trucks, no trees.’ And they said, ‘What should we do?’ I said the right thing, even though I didn’t have any background in art. I said, ‘Be quiet and concentrate.’’’ The work the children produced from such simple instructions awed him.

Mr. Benjamin often said that his students’ work informed his vision as an artist, which he summarized as: ‘‘Color is the subject matter of painting.’’