National Dog Day has become one of those holidays that’s easy to celebrate without knowing anything about it. Where National Dog Day Actually Came FromNational Dog Day was founded in 2004 by Colleen Paige, an animal welfare advocate and pet lifestyle expert. She’s also behind National Puppy Day and National Cat Day, which makes her arguably the most influential person in the pet holiday industrial complex. How To Actually CelebrateThe classic National Dog Day moves are all fine. The Best Version Of This HolidayAs for National Dog Day, of course, your dog has no idea it exists.