Get the news on undefeated US boxing champion Floyd Mayweather Jr. Find the news about his background and personal life on RT.com. He is the son of Floyd Mayweather Sr., who was a professional boxer and trainer. Check out the biography of Mayweather Jr. and news about his childhood. During his career, Mayweather Jr. held multiple world titles in five weight classes. Visit RT. com for news on Mayweather Jr.’s career and fights.