The Hall of Famer lettered in football, basketball, baseball and track while at UCLA. He broke the MLB color barrier becoming the first black baseball player, which began the process of integration in the sport, in 1947. He was the 1949 NL MVP.
The three-time World Heavyweight Champion was an Olympic gold medalist and SI's "Sportsman of the Century." He had the personality of all personalities, the swagger that came to define a champion.
The five-time NBA MVP won six NBA titles and was Finals MVP each time he won a title. One of the greatest basketball player of all time. Most influential basketball player of all time.
Lombardi coached the Packers to five NFL titles, including first two Super Bowls. The Super Bowl trophy is named after him. He has influenced every NFL coach in one way or another.
Some other contenders that came extremely close to making the final cut
Some of the more clever options I heard
Babe Didrikson Zaharias