Final answer:
No, Sidney Poitier is not the only actor to win three Oscars for three films in one year. Walter Brennan and Faye Dunaway have also achieved this feat.
Step-by-step explanation:
No, Sidney Poitier is not the only actor to win three Oscars for three films in one year. The first actor to achieve this feat was Walter Brennan, who won three Academy Awards for Best Supporting Actor in 1936, 1938, and 1940. He won for the films 'Come and Get It,' 'Kentucky,' and 'The Westerner.' Sidney Poitier is also not the only actor to accomplish this. In 1977, actress Faye Dunaway won three Oscars in one year for her roles in 'Network,' 'Chinatown,' and 'Barfly.'