LeRoy Neiman, whose brilliantly colored, impressionistic sketches of sporting events and the international high life made him one of the most popular artists in the United States, died on Wednesday in New York. He was 91.

Mr. Neiman's kinetic, quickly executed paintings and drawings, many of them published in Playboy, offered his fans gaudily colored visual reports on heavyweight boxing matches, Super Bowl games and Olympic contests, as well as social panoramas like the horse races at Deauville, France, and the Cannes Film Festival.

A native of St. Paul. Minn., Mr. Neiman quite consciously cast himself in the mold of French impressionists like Toulouse-Lautrec, Renoir and Degas, chroniclers of public life who found rich social material at racetracks, dance halls and cafes.

Often he painted or sketched on live television. With the camera recording his progress at the sketchpad or easel, he interpreted the drama of Olympic Games and Super Bowls for an audience of millions.

When Bobby Fischer and Boris Spassky faced off in Reykjavik, Iceland, to decide the world chess championship, Mr. Neiman was there, sketching. He was on hand to capture Federico Fellini directing "8 1/2" and the Kirov Ballet performing in the Soviet Union.

In popularity, Mr. Neiman rivaled American favorites like Norman Rockwell, Grandma Moses and Andrew Wyeth. A prolific one-man industry, he generated hundreds of paintings, drawings, watercolors, limited-edition serigraph prints and coffee table books yearly, earning gross annual revenues in the tens of millions of dollars.

Mainstream art critics either ignored him completely or, if forced to consider his work, dismissed it with contempt as garish and superficial — magazine illustration with pretensions. Mr. Neiman professed not to care.

"Maybe the critics are right," he told American Artist magazine in 1995. "But what am I supposed to do about it — stop painting, change my work completely? I go back into the studio, and there I am at the easel again. I enjoy what I'm doing, and feel good working. Other thoughts are just crowded out."

His image suggested an artist well beyond the reach of criticism. A dandy and bon vivant, he cut an arresting figure with his luxuriant ear-to-ear mustache, white suits, flashy hats and Cuban cigars.

"He quite intentionally invented himself as a flamboyant artist not unlike Salvador Dali, in much the same way that I became Mr. Playboy in the late '50s," Hugh Hefner told Cigar Aficionado magazine in 1995.

A native of St. Paul Minn., he showed a flair for art at an early age, and studied at the School of the Art Institute of Chicago, after serving in the military. While doing freelance fashion illustration for the Carson Pirie Scott department store in Chicago in the early 1950s, he became friendly with Hefner, a copywriter there who was on the verge of publishing the first issue of a men's magazine.

In 1954, after five issues of Playboy had appeared, Mr. Neiman ran in to Hefner and invited him to his apartment to see his paintings of boxers, strip clubs and restaurants. Hefner, impressed, showed the work to Playboy's art director, Art Paul, who commissioned an illustration for "Black Country," a story by Charles Beaumont about a jazz musician.

Thus began a relationship that endured for more than half a century and established Neiman's reputation.

In 1955, when Hefner decided that the party-jokes page needed visual interest, Mr. Neiman came up with the Femlin, a curvaceous brunette who cavorted across the page in thigh-high stockings, high-heeled shoes, opera gloves and nothing else. She appeared in every issue of the magazine thereafter.

"Playboy made the good life a reality for me and made it the subject matter of my paintings — not affluence and luxury as such, but joie de vivre itself," Mr. Neiman told VIP magazine in 1962.