It's Always Sunny in Philadelphia is an American television black comedy sitcom that premiered on FX on August 4, 2005. It moved to FXX beginning with the ninth season, and has remained there since. It was created by Rob McElhenney, who developed it with Glenn Howerton. It is executive produced and primarily written by McElhenney, Howerton, and Charlie Day, all of whom star alongside Kaitlin Olson and Danny DeVito