McClain was selected in the second round (27th pick overall) of the 1985 NBA Draft by the Indiana Pacers. He made his NBA debut on October 26, 1985 with the Pacers. He played only one season in the league, averaging 3.5 points per game. He was waived on September 30, 1986. Dwayne also played professionally in France, Canada, The Philippines, Indonesia and Greece before finishing his career in Australia.
McClain had an extremely successful career in the Australian NBL during the early 1990s, playing 105 career games with the Sydney Kings, averaging 25.4 points per game. He also played for the Brisbane Bullets and the Gold Coast Rollers.
He was the MVP of the 1989 Continental Basketball Association All-star game.