For this answer, I'll assume the intended meaning here of "non-human" is "non-Earthling." In any case, I found this URL interesting: http://sci-fi.lovetoknow.com/wiki/Aliens_on_Television
It doesn't say definitively who was the first alien to make regular TV appearances, but does say My Favorite Martian was among the earliest.
Also, how are we defining "regular TV appearances"? If the character has to be a series regular, I can't add anything to previous posts. However, if it means a recurring character, there's Marvin the Martian of Looney Tunes (and his illudium Q-36 explosive space modulator, of course [http://www.imdb.com/character/ch0030547/quotes]
). According to imdb (http://www.imdb.com/character/ch0030547/
), he's made 24 appearances, and many, if not all, have made their way to TV, particularly via a few of the features being made for TV, as well as many of them being repeated on 1968's Bugs Bunny/Road Runner Hour. The earliest was Haredevil Hare in 1948 and the most recent was Bah Humduck!: A Looney Tunes Christmas in 2006, although maybe we haven't seen the last of this character.