Question

Is Rick Harrison related to President Harrison

Answer 1

I'm sure that there's a Rick Harrison somewhere who is related to a President Harrison, but unless you tell us more about the specific Rick, there's no way to help you. (Also, it helps to know which country this President is from, and if President is his title or his first name!)

Answer 2

If your asking about Rick Harrison from Pawn Stars I believe in one of the episodes he said about being related distantly to  Presidents william and Benjamin harrison.  not directly, but  great nephew or distant cousin or something.