Berkshire Hathaway Chairman Warren Buffett and LeBron James seem like an odd couple.

But James’ friendship with the second richest man in the United States tells the story of another side of the Miami Heat superstar. As focused as James has been on his goal of winning NBA championships, he’s just as driven off the court about building a business empire and breaking the billion-dollar mark, an accomplishment golfer Tiger Woods was the first athlete to achieve.

“You have to get to know him,” Buffett said. “LeBron’s not initially really talkative. He’s savvy. He’s smart about financial matters. It’s amazing to me the maturity he exhibits. I know that if I had been famous at that age, I would have had trouble keeping my feet on the ground.”

Those are pretty big compliments coming from Buffett, the world’s leading investment guru, who at 82 could easily be the grandfather of James, 27. Yet the age difference and James’ lack of a college degree haven’t been a barrier to a friendship that includes Buffett providing occasional business advice.

Buffett isn’t the only high-profile executive James counts as a friend. You’ll find him in the company of people as diverse as Microsoft Chief Executive Steve Ballmer, Hollywood producer Tom Werner, Dallas Cowboys owner Jerry Jones and music mogul Jay-Z. It was actually James who introduced Heat owner and Carnival Chief Executive Micky Arison to Ballmer.

At an investment conference a few years ago attended by chief executives from some of the largest Fortune 500 companies, Buffett says his friend James could more than hold his own.

“People were more interested in meeting him than in meeting me,” Buffett said. “He doesn’t need me to introduce him, that’s for sure.”

Coming off the best season of his career, James needs no introduction to corporate America. The NBA’s most valuable player had his pick of endorsement offers and business opportunities as the Heat sets out to defend its championship. The first new deal puts James as a brand ambassador for Samsung’s new cellphone, the Galaxy Note II. Ads featuring James launched during the Heat’s opener this week.

“It’s really LeBron’s world right now,” said Bob Dorfman, executive creative director of Baker Street Advertising in San Francisco and the author of the Sports Marketing Report, who estimates any deals James signs will be a minimum of $1 million a year with a five-year term.

James was the fourth-highest paid athlete in the world last year with an annual income of $53 million — a number that would have been 20 percent higher without the salary cut for the strike-shortened season, according to Forbes. The majority of Lebron’s earnings — $40 million — comes from endorsements and business contracts with a high-profile roster that includes Nike, Coca-Cola and McDonald’s.

The only athletes ranked higher than James on the Forbes list are boxers Floyd Mayweather and Manny Pacquiao, followed by Woods. James edged tennis player Roger Federer and Lakers star Kobe Bryant — previously the NBA’s top earner.

James’ income is clearly on the upswing. Brands like winners, and it doesn’t hurt that James resides in a top media market like Miami. The Samsung deal is the first of what is expected to be a series of new endorsements and business deals.