LONDON — Anthony Caro, the leading British sculptor of his generation, died Wednesday of a heart attack, his family said. He was 89.

Caro, who made monumental sculptures with scrap metal, was active well into old age. His retrospective at this year’s Venice Biennale is on through Sunday, and he showed 12 monumental sculptures last summer here at the Gagosian Gallery.

“I would be bored not to work, and I would be bored to try and repeat myself,” Caro said in a June interview. “That would be terrible. So I keep going.”

The son of a stockbroker, Caro studied engineering at Cambridge University. After serving in the Royal Navy from 1944 to 1946, he studied art against his father’s will. In 1951, he approached the sculptor Henry Moore to ask for a job, and became his assistant for the next two years.

From the 1960s, Caro switched from clay to steel, and spent time in the United States, an experience he described as life-changing. He taught for two years at Bennington College, and got his first New York solo exhibition in 1964. Five years later, he had a retrospective show at the Hayward Gallery in London.

The 1960s were a turning point in other ways. In 1961, Caro made his first polychrome (meaning colored) sculpture, and made often brightly painted works for the next decade. He also did away with the plinth, placing sculptures on the viewer’s level. Works of the period such as “Month of May” (1963), though made of heavy steel girders, sheets and pipes, look carefree, and seem to float in the air.

In 1970, he abandoned color for darker sculptures that often retained the texture and hue of their scrap-metal components. Though these later pieces were critically respected, his reputation rests mainly on works made between 1960 and 1970. He was knighted in 1987, becoming Sir Anthony Caro.

“Anthony Caro was one of the outstanding sculptors of the past 50 years, alongside David Smith, Eduardo Chillida, Donald Judd and Richard Serra,” Tate Director Nicholas Serota said Thursday.

“In the sixties, he established a new language for sculpture in a series of elegant, arresting, abstract steel sculptures placed directly on the ground,” Serota said.

“His development of this vocabulary, building on the legacy of Picasso but introducing brilliant color and a refined use of shape and line, was enormously influential in Europe and America.”

Caro’s art-market values never soared the way those of some contemporaries did. The most a Caro work fetched at auction was $2.45 million, paid in February 2006 at Sotheby’s London for “Sculpture Two” (1962).

He saw the art-market frenzy as a negative trend. “The crazy-price things, I think, are destructive of the art, because people get too conscious of money,” Caro said in a 2010 interview.

He remembered a time when, after an exhibition, friends would ask how it went, or whether critics liked it. “Now they say, ‘Did you sell?’” he said. “It puts the wrong emphasis.”