McIntosh attended the University of Wisconsin, where he was a standout tackle for the Wisconsin Badgers football team from 1996 to 1999. As a senior in 1999, he was a team captain and a first-team All-Big Ten selection, and was recognized as a consensus first-team All-American. McIntosh was a member of the Badgers' Rose Bowl championship teams in 1999 and 2000.
Along with Shaun Alexander, McIntosh was drafted by the Seahawks in the first round in 2000; McIntosh's playing time increased as the 2000 season went on. McIntosh started in 10 games for the Seahawks as a rookie, but was limited to three starts in 2001 because of a recurring neck injury he suffered during training camp. McIntosh retired from the NFL after the 2002 season.