Though he's Maori, he's only played a Maori in a couple of movies, including Whale Rider (2002). He has been cast as many other dark-skinned ethnicities, having played, among others, Mexican-Americans, Colombians, Arabs, Persians, and Chechens.
[on Whale Rider (2002)] I've been waiting for this film for a long time. It's fun to go off and put on a disguise and pretend to be someone else, but to be able to get back to myself and my culture, that was just more than really nice, y'know - it was vital.
