Lewis was drafted 40th overall in the 2004 NHL Entry Draft by the Atlanta Thrashers. He played collegiate hockey with Dartmouth College of the ECAC. During his freshman season he had 25 points, including 3 goals, in 34 games. His 25 points was the second-highest for a freshman in the history of the college. In four seasons he played in 120 games, and had 13 goals and 64 assists for 77 points.