More than two decades after Romero vacated the role, we got our next legit Joker. By then, comics had changed—and Batman's world in particular reflected the medium's dark turn. Jack Nicholson's interpretation of the character is, for many fans, the Joker that represents the most nostalgic era of Batman (and a whole raft of childhood nightmares), so it's hard to judge his work in Tim Burton's 1989 Batman objectively today, but he earned no shortage of critical praise. While Roger Ebert only gave the movie two stars, he lauded Nicholson's Joker as the film's most important character; The Hollywood Reporter, meanwhile, called Nicholson "over the edge" (in a good way), decades before anyone could possibly anticipate even more insane Jokers.
Burton brought more realism to Gotham, and Nicholson showed that super-villains don't just sprout into deranged existence—they often evolve from flawed human characters, and that's just one reason why his Joker remains a standard-bearer. Maybe it's the film's visual design, or the Joker viciously frying a man alive using nothing but a joy buzzer, but Nicholson's anger and menace, paired with unpredictable moments of silliness and joy, still feel timeless.