Jim Henson provided the voice of the baker in the "Song of 2/3" segments, as well as all the other number song videos to soon follow. The actor playing him on screen is stuntman Alex Stevens.
The series' premiere marked the debuts of Big Bird and Oscar the Grouch, as well as the nationwide debut of Ernie, Bert, Gordon, Susan, Bob, and Mr. Hooper. Kermit the Frog and a yet-to-be-named Cookie Monster were existing Muppet characters.