Thanks for the birthday wishes (this question was from Sunday). I do believe that Obama is the only President besides FDR to be sworn in on four occasions. We’ve had a few official swearing-in ceremonies when March 4th (the original Inauguration Day) or January 20th fell on a Sunday and the President had to be officially sworn in ahead of the ceremonial Inauguration the next day, but Obama, of course, had the extra oath of office ceremony in 2009 because he and Chief Justice Roberts flubbed the oath the first time. Off the top of my head, I can’t think of any other Presidents who might have done it four times.