The performance by Gregory Peck as Atticus Finch won him the Best Actor award for both the Academy Awards and the Golden Globes. His performance has been called one of the greatest in film history, with one poll listing it in the Top Five of all time. The American Film Institute called Peck's role as Atticus Finch the #1 greatest hero in American films. Peck's performance elevated the status of Atticus to an almost legendary level, and attorneys all over the country use him as an example of the quintessential courtroom lawyer.
Peck accepted the role almost immediately, and most of those involved with the film thought he merely portrayed Atticus as an extension of his own gentlemanly persona. The movie has never been remade in part because no one could ever be cast as convincingly as Peck in the role of Atticus Finch.
Mary Badham, who portrayed Scout, was nominated for the Best Supporting Actress Oscar--the youngesst ever to be nominated-- but she failed to win. (Patty Duke won for The Miracle Worker.) Her performance was also superb, especially considering it was her first film appearance. Her performance was one of natural simplicity, and like Peck's portrayal of Atticus, it would be hard to imagine anyone else in the role.