He used to be more sinister — he was able to hypnotize and stun people and he laughed in typical scary-villain-type fashion after completing a count of something and thunder and lightning would occur.
He was quickly made more appealing to little kids, though. He is apparently quite the ladies’ man — he has been linked to Countess von Backward, who loves to count backward; Countess Dahling von Dahling and Lady Two.
I always remember the “more sinister” version of Count von Count. If you had asked me his name ten minutes ago, though, I would have just said simply, “The Count!” I had no idea (or had completely forgotten) that his name was Count von Count until I just read this excellent article on some Muppet back-stories (which I found on MeFi). I also didn’t know the bit about him being a ladies man, although I vaguely remember Countess von Backward.