Wallace was selected for the City vs Country Origin match in 2008. In May, 2008, Wallace was selected as halfback for New South Wales for game I of State of Origin on 21 May at ANZ Stadium. With his first touch of the ball, he made a line break. He also had a hand in two tries and placed a pin point accurate kick for Anthony Quinn to score the second try of the night. He made only one error and took many hits from Queensland players, making 29 tackles.