How bout some of the main characters in 'Battle of Algier's'?? Fantastic, naturalistic acting from non-performers, (or should we say people with no prior experience in 'being' in front of a running camera?)
I think of two "non-actors" who played their roles well, and both were attorneys - in real life and in the film.
One was the prosecuting attorney in "Goodfellas" - the man who convinced Henry Hill to turn state's and rat out his croneys...the man who played him was the real life attorney who prosecuted the mob in that story.
The second was one of the attorneys in "The Insider" with Russell Crowe (the other was played by "D-Day", of Animal House fame)...he also was a real-life attorney who helped bust the tobacco companies in that movie and in real life.
