Green, 18, is a dual citizen of the US and Germany, but wore the latter's colours in official FIFA competition – a qualifier for the Under-19 European Championship.
But FIFA approved a one-time change of association, much to the delight of USA coach Jurgen Klinsmann.
"We are obviously thrilled," Klinsmann said.
"We appreciate FIFA's effort in getting his paperwork approved, and are excited to have him on board for the game against Mexico on April 2."
The Florida-born Green spent time with the US team in Frankfurt before the March 5 friendly against Ukraine.
He has been invited to be involved in preparations for the clash against Mexico.
Green signed with Bayern in November 2013 but is yet to make his first-team debut for the Bundesliga and European champions.
