At the age of 11, she was chosen by a casting director from among hundreds of girls at her primary school in Mt. Wellington to play the memorable role of Paikea in Whale Rider (2002). Despite her lack of previous acting experience, Castle-Hughes received an Oscar nomination for Best Actress, making her -- at 13 years old -- the youngest actress ever to be nominated in this category.
In 2004, George Lucas cast Castle-Hughes to play the new Queen of Naboo in Star Wars: Episode III: Revenge of the Sith (2005).