MLS's marketing arm, Soccer United Marketing, will oversee sales, PR and marketing, as well as any future strategic alliances for the club.
Six matches between FC Barca and MLS teams are also part of the package, although details are still being finalised.
Ferran Soriano, the Barcelona vice-chairman, said: "We want global brand equity. Football is one of the few sports that can be truly global. But, to be global, we have to have strong roots."