Green Card holders can join the US Army and they have the legal right to do so. US citizens and lawful permanent residents of the United States alone can join the US Army. If you feel that you are eligible, you can go to a recruitment office and talk to a recruiter. However, the army may not accept anyone who wishes to join. As a Green Card holder, you must be qualified and must meet the general requirements to join the US Army. Lawful permanent resident status that is granted to you alone may not be sufficient to join the army and your Green Card must be valid and if your card is about to expire, you may not be able to enlist. In order to enlist, your Green Card must be valid until you complete an enlistment.
You also need to remember that the recruiters may not be able to help you to get a Green Card and they cannot help you with the immigration process. If you are not a permanent resident and if you do not hold a Green Card and if you wish to join the US Army, you must contact the USCIS and take necessary steps to obtain a Green Card. Similarly, being a non US citizen, you need to remember that if you have already served in another country’s army, you may not become eligible to join the US Army.
Members of the US armed forces are granted a variety of benefits and they get special preference while they apply for US citizenship. They can apply for US citizenship, one year after joining the US Army. It is well known that the permanent resident cardholders will have to wait for years to apply for US citizenship but the citizenship process is faster for the members of the armed forces. However, people who enter into the United States lawfully, alone can join the US Army and the lawful permanent residents and US citizens who wish to join the army must be physically present in the country, to enlist. Remember that, if you lie about your status, you will be punished and you will never be able to apply for immigration benefits.