Don Garber, addressing delegates at the Soccerex business convention, said Beckham's move to the U.S. had been a success and dismissed media speculation the England player would decide against returning when the finals in South Africa were over.
Garber said: "David will be back after the World Cup, no doubt about that. He has been a success. There are always going to be people, particularly in England, that look at everything and don't see the positives.
"Our league is on the map globally, he's one of the most popular people on the planet and he plays in Major League Soccer for Los Angeles Galaxy.
"That in itself has shown the world we are serious in that we have one of the great international players in our league," added Garber.
"Have there been challenges with him going back and forth? Absolutely but sometimes that kind of buzz is good. Football is a phenomenon in the United States now."
Beckham, England's most capped outfield player with 115 appearances, could face the U.S. in a Group C tie in Rustenburg on June 12.
"It will be one of the most popular sports events in America for quite some time," said Garber. "ESPN is going to promote it more than any other event in their history, it's a rematch of the 1950 World Cup (tie) which we surprisingly won.
"It's Beckham v Landon Donovan and that could be a great story. I hope David Beckham plays and he's certainly been spending a lot of time in Milan to give him the best chance of playing."
Garber also said he was hopeful a dispute between the MLS and its players would be resolved. MLS players want more freedom from the league over salaries and contracts.
"We'll get through it, we'll find a system that works for us and the players," he added.
