A person might have a EAD card while their green card is in process. Since the EAD card allows one to work anywhere in the US, would that mean that the person can work in the US army?
You do not have to be a citizen to join the military. However, you do need your permanent Resident Alien card.
However, there is nothing stopping you from visiting a recruiter and starting the process. WIth the testing and everything, it normally takes 1-3 months to get in anyways.
By then, you should have your permanent card in hand.
