Mighty Mouse Playhouse first aired on CBS Saturday mornings, beginning December 10, 1955. That date is important because the show helped put the idea of Saturday morning cartoons on the map.
Mighty Mouse had actually started earlier in theatrical cartoons from Terrytoons, debuting in the 1942 short The Mouse of Tomorrow. But TV is what made him a household name. CBS repackaged the older Mighty Mouse cartoons for television, and suddenly kids could see him right at home instead of at the movie theater.
The show had everything kids loved: a tiny hero with super strength, flying rescues, villains, danger, and that unforgettable theme line: “Here I come to save the day!” Mighty Mouse usually showed up just in time to save the helpless and defeat the bad guys.
Looking back, Mighty Mouse Playhouse feels simple now, but it was a big deal. It helped prove that Saturday morning could belong to kids, cereal bowls, pajamas, and cartoons.