( CNN ) -- Iconic American artist LeRoy Neiman , known for his trademark handlebar mustache and his bright , impressionistic portrayals of the world 's top sporting events , died in New York on Wednesday . He was 91 . The cause of death was not immediately known . `` We mourn the passing of such an extraordinary and talented man , '' said a statement from his wife Janet and his family , who were with the artist when he died Wednesday evening at New York-Presbyterian Hospital in Manhattan . Although his paintings captured everything from U.S. presidents to jazz musicians to the powerful animals of Africa , Neiman became best known for his bright , bold sketches of the sports world , capturing its motion and emotion in his brushstrokes . The most influential artist you 've probably never heard of . Neiman `` has the journalistic talent , as well as the artistic ability , to convey the essence of a game or contestant with great impact , from the Kentucky Derby to Wilt Chamberlain , from the America 's Cup to Muhammad Ali , from the Super Bowl to Bobby Hull , '' sports writer Nick Seitz said . He was named official artist of the Olympic Winter Games in Lake Placid and in Sarajevo as well as the Summer Olympics in Los Angeles . Neiman 's powerful imagery of the boxing ring , including fight posters and program covers for the historic Muhammad Ali-Joe Frazier fights , earned him a spot in the International Boxing Hall of Fame in 2007 . He was so closely identified with the world of boxing that actor/director Sylvester Stallone tapped Neiman to appear in four of his `` Rocky '' movies . Neiman was born June 8 , 1921 , in St. Paul , Minnesota , the son of Lydia Sophia Serline and Charles Julius Runquist . He later took the surname of one of his stepfathers , after his biological father abandoned the family , his biography says . He enlisted in the army in 1942 , serving during World War II . Neiman was in the invasion of Normandy and fought in the Battle of the Bulge , according to his publicist Gail Parenteau , later attending Chicago 's prestigious School of the Art Institute on the G.I . Bill . Neiman taught at the Institute for 10 years early in his career before gaining recognition as a contributing artist for Playboy in the 1950s . The series `` Man at His Leisure '' appeared in the magazine for 15 years , showing the artist 's impressions of sporting events and social activities . Included in the series was the Grand Prix in Monaco , the Beatles in London and the running of the bulls in Pamplona , Spain . Staying true to his style , Neiman 's public persona was as almost as colorful as his artwork . `` I guess I created LeRoy Neiman , '' the artist once said , according to the biography on his website . `` Nobody else told me how to do it . Well , I 'm a believer in the theory that the artist is as important as his work . '' Thomas Kinkade , popular artist , dies at age 54 .
LeRoy Neiman is best known for his paintings of sports figures , especially boxers . Sylvester Stallone tapped Neiman to appear in four of his `` Rocky '' movies . In the early 1970s he was commissioned by a group called The Artists Fund to create an artwork that would be displayed at their annual gala dinner.