Arum? Don king? floyd? Oscar? As much as i dont agree with him most of the time. Arum has given us the best fights out there. consistently.
Tex Rickard...!!! Brought the first live radio broadcast of a title fight Brought boxing its first million dollar fight Built Madison Square Garden Cross promoted boxing with other sports (Rickard owned the New York Rangers of the NHL) and the Public Announcer would mention upcoming fights during stoppages in the hockey game...!!!
Tex Rickard by a mile. He had the first $1M gate and he had stadiums that seated in excess of 100,000 people. Dempsey was making more than Babe Ruth, and of course you had Johnson - Jeffries, which was one of the most anticipated fights of all time. Here's a little blurb about him. As "the Father of Madison Square Garden," he promoted over 200 fights, including some of the most notable of the 20th century: the "Longest Fight," the "Great White Hope," fight, and the famous "Long Count" fight. Along the way, he rubbed shoulders with some of history's most renowned figures, including Teddy Roosevelt, Wyatt Earp, Bat Masterson, John Ringling, Jack Dempsey, and Gene Tunney
Don King had a great fifty year run, better than Arum in the same time period. There have been some good ones over the last century: Tex Rickard, Mike Jacobs (owned Madison Square Garden), Aileen Eaton (ran the LA scene), George Parnassus (specialized in lowerweights and South West), Sam Silverman (ran New England) Frank ****** and Jack Solomon ran things for about twenty years apiece in England. Wilfried Sauerland ran things for a while in Germany. Akihiko Honda in Japan.
Rickard was important, influential, and effective, but is he the greatest? He was like P.T. Barnum with his fingers in every entertainment medium. He promoted wrestling and other sports too. He promoted 200 fights, but Sam Silverman promoted 10,000. It's not purely a numbers game but the guys I've listed have all put together thousands of fights. Rickard promoted Dempsey, Akihiko Honda promoted Tyson, Arum and King promoted Ali, etc.
Don King. He put on all the fights without too much protection(until he ran out of boxers to exploit) He sold fights himself with his strange hair and personality.