join the U.S. military, non-citizens must be living permanently and legally in the United States. Non-citizens must also have permission to work in the United States, possess an I-551 (Permanent Residence Card), have obtained a high school diploma and speak English.

Undocumented immigrants are generally barred from serving in the military, though occasionally (especially in times of military need) an undocumented person might be allowed to join the armed forces in spite of this rule.

If you are serving or have served in the U.S. armed forces and are interested in becoming a U.S. citizen, you may be eligible to apply for naturalization under special provisions of the Immigration and Nationality Act (INA).