Where does Michael's death record state he was born and when? If not in the U.S., have you looked for a naturalization record for him? Those records are, sometimes, quite detailed. If he was born in the U.S., then you should look for his birth record in the birth location, depending upon the time period, as well as checking U.S. census records.
You may need to go back to previous generations of your family and document each event (major event--birth, marriage, death) to get more clues that will provide you leads to the previous generation of your family. The records you find will tell you where you should look for more information.