Which fighter won the most rounds during their career?

I too immediately thought of a fighter with mostly decision wins and the three I thought of right off the bat was Johnny Dundee, Duilio Loi and Nicolino Loche. For what it's worth.

 

If a fighter won a lot of rounds in his career or most, we have to wonder if he fought top fighters or enough of them. In many ways the guys who are multiweight titlists who fought other greats will have lost many rounds. That is what we want, competitive fights.

 

How has Mayweather not been mentioned

 

You must have heard right. The good news we can always check the score cards and see for ourselves.