If a us citizen marries a Mexican illegal immigrant in the us and has 20 years of deportation can he still get the green card and become a resident of the US?

to my knowledge, if you as an American citizen are LEGALLY married to an illegal, all that you have to do is go to your local Immigration office and apply for his residency. it is better if you are married in the u.s. before applying. if you guys married in the u.s. so much the better. make sure that he does not have a criminal record or that is it. if you married outside the u.s. what i would do is to marry again in the u.s. so that immigration will "recognize" said marriage, but yes, as a u.s. citizen, applying for your spouse is one of your privileges and rights for being a u.s. citizen...good luck