You could answer this in a few different ways:
First of all, you could say that Pope Julius I made Christmas in the 300s. He was the one who decided that Christ's birth happened on December 25. Scholars think that this was done to give Christians something to celebrate when all the pagans were celebrating Saturnalia.
The second way I'd answer it is that Christmas in the United States and England was created in the 1800s. (And not by any one person.) For example, Christmas was not a national holiday until 1870. It was earlier in the century that, for example, Charles Dickens wrote A Christmas Carol. This story was one of the things that helped move Christmas towards being the big deal (not just religiously) that it is today.