Each Network’s First Cartoon Series: Nickelodeon and Cartoon Network

Cartoon Network: The Moxy Show 1993
The Moxy Show, this show came out in 1993, and tells the story of Moxy, a Dog who is a Janitor at the Cartoon Network Studios and while he cleans the offices, he has a secret closet where he steals airtime from other Show’s Signals.

Nickelodeon:
We have a Three Way Tie as all three Premiered on August 11th 1991: Its Doug, The Rugrats, and The Ren and Stimpy Show. Interestingly enough, Dough eventually appeared on the Disney Channel. Speaking of which

Disney Channel: This one is a little semantical as I don’t want the first Disney animation, but rather the first to be aired on the Disney Cable Channel Which is
Good Morning, Mickey! This series was released on April 18th, 1983

Fox:
The first Cartoon Series on Fox was the Simpsons, which became an official series 1989, but it started off as Short Animated Skits in-between the Tracey Ullman Show in 1987.

CBS:The first regularly scheduled Cartoon on CBS were The Adventures of Farmer Al Falfa which aired in 1949, most Animations prior like Looney Tunes and Steamboat Willie were only shown in Movie Theaters before eventually coming to TV.

ABC:
As for ABC, their first regularly scheduled Cartoon was Matty’s Funday Funnies which first aired in 1959.