Heath Ledger became the second performer to win a posthumous acting Oscar. The first was Peter Finch (in 1977, for Network (1976)).
Nicole Kidman had at one point been set to play Kate Winslet's Oscar winning role of Hanna Schmitz in The Reader (2008), but passed on the part due to pregnancy. Also, Marion Cotillard had been briefly considered for the role of Hanna before Winslet was cast. Ironically, both Kidman and Cotillard were two of the presenters who awarded Best Actress winner Winslet her Oscar trophy.
For the first time, the Academy kept the list of presenters secret.
Slumdog Millionaire (2008) was the first Best Picture winner to receive more than four Oscars since The Lord of the Rings: The Return of the King (2003).
Doubt (2008) was the first film to receive four Oscar nominations for acting since Chicago (2002). Chicago went on to win one, but Doubt didn't win any.