The Mouseke-ears were designed by Disney storyman/Big Mooseketeer _Roy Williams. He based them on a gag in The Karnival Kid (1929), in which Mickey doffed the top of his head - ears and all - like a hat.
Annette Funicello has stated in interviews that, upon being cast for the show, she told Walt Disney that she wanted to change her last name to one that sounded more "American". To his credit, Disney told her to keep her original last name because, "once someone remembers it, they will never be able to forget it".
In the animated inserts, Walt Disney provided the voice of Mickey Mouse for the very last time. He retired from voicing the character during the production of Fun & Fancy Free (1947) because he simply could not do the required falsetto anymore, and let sound effects man James MacDonald take over.
Although the show was filmed and broadcast in black and white, all of the animated segments - the opening theme, Mickey's introductions and farewells, the Jiminy Cricket shorts, etc. - were filmed in color.