He has a relatively quiet demeanor and lets his action speak more than his words, Wahl said, and it doesn't hurt that he's married to a Spice Girl and is the object of much adoration.
"I think part of it is, he's a tremendously good-looking guy who has embraced the positive and negative that comes with being a global celebrity," Wahl said. "Women love the guy."
Which explains why he has been found on billboards and in subway stations over the years pimping everything from Samsung and Sainsbury's to Emporio Armani and his own H&M clothing line. Even his son Romeo, 10, is a Burberry model.
While it may be difficult to ascertain exactly how Beckham popularized the American game or whether his MLS Cups or sex appeal were bigger contributions, he certainly spurred Americans' appetite for the sport, if only by being here.
"His biggest achievement," said Wahl, "was signing with the MLS."