This is a difficult question to answer definitively as both actors brought their own unique and unforgettable interpretation to the iconic character of Joker in two very different films. However, if we compare the two performances side-by-side, I believe Heath Ledger’s portrayal is slightly superior.
Jack Nicholson’s Joker in “Batman (1989)” was undoubtedly one of the most memorable and unnerving cinematic villains of all time. His performance was unhinged, maniacal and completely unpredictable – exactly what you would expect from The Joker. However, I felt that at times his acting was a little too over-the-top and campy for my taste.
On the other hand, Heath Ledger’s take on the character in “The Dark Knight (2008)” was much more grounded and believable. His Joker was still just as dangerous and erratic as Nicholson’s, but there was an added layer of pathos and tragedy to his performance that really made it stand out. Ledger truly embodied the role in every way, and it is no wonder he posthumously won an Oscar for his efforts.
In conclusion, both Jack Nicholson and Heath Ledger gave outstanding performances as The Joker, but I believe Heath Ledger slightly edges out his predecessor due to the depth and complexity of his portrayal.