FOZZIE!!!!!! He's definately the first!!!!
Also, Animal, Prof. Hastings, Bert, Grover, Cookie Monster, Harvey Kneeslapper, uhh.... Piggy of course, Aw... Sam the Eagle, and.. Okay, pretty much all his characters.
And does Yoda count as a Muppet? Everyone is split. Most people say he is, the rest says he's not! And if he's not, but we still count him because he's a Frank Oz characte, do John Lovelady and Kevin Clash characters count as Muppets, even though they aren't???
I'm confused!!!