I have a misdemenor can I still join?

Depends on the outcome of the courts. If your records are in fact supposively sealed you may be in the clear. However, you want to be forthcoming with whatever recruiter you talk to. Believe me, they've heard it all, either in person or by word of mouth. I'm commend you on wanting to square your life away and becoming a part of something greater then yourself, hopefully serving proudly this nation. Good luck in court.