Is there a million dollar bill? If so, whose picture is on it?
Sorry to disappoint you, but the largest bill ever printed by the U.S. mint is the $100,000 bill, which carries Woodrow Wilson's portrait. Even if you're in the habit of purchasing small Caribbean republics with cash, you're unlikely ever to see one—it is used only in transactions between Federal Reserve System and U.S. Treasury Department.
Here's a complete listing of the portraits and designs on U.S. currency.