Mark Hamill's Joker from the Batman: The Animated Series will not return as the Clown Prince of Crime in the future according to the actor and it's for a touching reason. Hamill, who is known worldwide for his role as Luke Skywalker in the Star Wars franchise, has developed another, just-as-iconic performance as Batman villain Joker over the years. Hamill first played the character in 1992, in the groundbreaking Batman: The Animated Series, and has since voiced the character in several spinoff series, video games, and films.
https://screenrant.com/batman-joker-mark-hamill-return-no-explained/