Step 1: Check what the question wants.
It asks for the longest running English language TV cartoon that started in 1969 and still airs new content on Cartoon Network.
Step 2: Match each show to that description.
Tom and Jerry started in 1940 as theatrical shorts, not as a TV series made in 1969. Popeye began even earlier, in 1933, also as theatrical cartoons. Johnny Bravo is a 1990s Cartoon Network original, so it does not fit the 1969 launch date at all.
Step 3: Confirm the correct match.
Scooby-Doo, Where Are You! premiered in 1969 and the franchise has run continuously since then with new series and specials, making it the longest running English language TV cartoon franchise in history. It airs regularly on the Cartoon Network today.
Final Answer:
The show that matches every clue in the question, the 1969 launch and continuous run, is Scooby Doo. \[ \boxed{\text{Scooby Doo}} \]