Clement Greenberg, the art critic who propelled the career of Jackson Pollock and helped to establish Abstract Expressionism as a major artistic movement, died on Saturday at Lenox Hill Hospital. He was 85 years old and lived in Manhattan.

He died of complications from a four-year bout with emphysema, said his daughter, Sarah Dora Greenberg. He was taken to the hospital from his apartment on May 2 because he had trouble breathing.

Mr. Greenberg's career spanned more than 50 years, and he became something of a legend in his own right. He was among the last survivors of the group of artists and critics associated with the Abstract Expressionist movement, and his advocacy of such artists as Pollock was crucial to the movement's coming of age and has been documented in the art histories of the period. His adamantly formal approach to looking at art was so closely linked to his name that it was often referred to as Greenberg formalism. On Making Criticism Original

But he was also known for keeping art journalism to a high standard of engagement and responsibility. He said he felt that art criticism had to be as original as the art it talked about and that it should be pointedly discriminating.

"Art criticism," Mr. Greenberg wrote, "is about the most ungrateful form of 'elevated' writing I know of. It may also be one of the most challenging -- if only because so few people have done it well enough to be remembered -- but I'm not sure the challenge is worth it."

He was born in the Bronx in 1909, and grew up in Norfolk, Va., and Brooklyn. He was the eldest son of a Jewish immigrant from Russia who owned a clothing store. By the time he was 4, he drew with great zeal, propelled by his own ability to bring objects and people to life.

But his parents did not share his love of art or even appreciate it. Later in life, he described them as "barbarians," who threw away every scrap of his artwork and who perhaps unwittingly laid the foundation for their son's theorizing on the mutual antagonism between art and the average person.

After graduating from Syracuse University in 1930, where he majored in literature, Mr. Greenberg traveled to New York City, where he settled. It was the height of the Depression and Mr. Greenberg was unable to find any work. So he decided to teach himself Latin and German and was eventually hired to translate books.

A pivotal moment in this period of his life came in 1937 when he was hired as a customs clerk by the Federal Government. Assigned to the appraisers-store division of the customs service on Varick Street in lower Manhattan, he began to spend idle hours at the office composing essays on culture. This work eventually found its way into the pages of Partisan Review, the unofficial mouthpiece for a group of thinkers known as the New York intellectuals.

Mr. Greenberg emerged on the American art scene when it was still relatively small, and critics belonged to the insular world of the artists themselves. Among these artists was an obscure painter named Jackson Pollock, who was earning little money on the Works Progress Administration Federal Art Project.

Later in life, Mr. Greenberg said he remembered liking Pollock when they were introduced, by Lee Krasner, the painter and Pollock's wife. (But Mr. Greenberg once acknowledged that he was troubled by Pollock's alcoholism and said that Pollock was unable to paint when he was drunk.)

Mr. Greenberg came to lavish great praise on Pollock's work, though very few people noticed at first. But he persisted and he became linked with Pollock as the French critic Felix Feneon was to Georges Seurat and the English critic John Ruskin was to J. M. W. Turner.

He also went on to become one of the most influential supporters of the legendary Abstract Expressionist period, turning on it his formidable eye and his brisk and lean style of writing. He did not give the movement unqualified support, to be sure, and he confessed that he himself had underestimated a number of artists in the period. Of Theodoros Stamos, he once said: "I scorched his show and I was wrong. You keep on learning."

He once summarized the work of an art critic this way: "Let nothing come between you and art, nothing, no ideas, nothing. The idea is to see enough: that's how you acquire taste. Don't even look at the name on the label."

But he was also hard pressed to explain how he arrived at esthetic judgments. "When it comes to explaining esthetic verdicts," he said, "far better minds than mine haven't gotten anywhere near it. When something really works, you're helpless. The toughest part of art criticism is praising because then you use the same words all the time. You can say the same thing in praise of a Bouguereau as you can of a Titian. When you don't like something, the words come more readily."

In addition to providing written criticisms, Mr. Greenberg was an avid visitor of studios where he would routinely offer advice to artists. His comments were often simple. "You say, 'That's good' or 'That's not good enough,' " he said of his visits. "But you never say, 'That's bad' in an artist's studio."

Although he is still a household name in many art-world households, he had written little since the early 1960's and had primarily lectured outside New York City.

In addition to his daughter, he is survived by his wife, Janice Van Horne Greenberg, and his brother, Martin Greenberg of Cobble Hill, Brooklyn.

Photo: Clement Greenberg (The New York Times, 1991)