From Wikipedia the free encyclopedia William Harrison Jack Dempsey June 24 1895 May 31 1983 nicknamed Kid Blackie and The Manassa Mauler was an American professional boxer who competed from 1914 to 1927 and reigned as the world heavyweight champion from 1919 to 1926 A cultural icon of the 1920s Dempseys aggressive fighting style and exceptional punching power made him one of the most popular boxers in history Many of his fights set financial and attendance records including the first milliondollar gate Dempsey is ranked as tenth on The Ring magazines list of alltime heavyweights and seventh among its Top 100 Greatest Punchers while in 1950 the Associated Press voted him as the greatest fighter of the past 50 years He is a member of the International Boxing Hall of Fame and was inducted into The Rings Boxing Hall of Fame in 1951