McShane attended Robert A. Millikan High School, where he practiced football and track.
He transferred to California Lutheran College after his sophomore season to play defensive tackle under head coach Bob Shoup.
As a junior, McShane was named NAIA District II second-team, receiving the team's Iron Man and most valuable lineman awards.
In 2008, he was inducted into the California Lutheran University Alumni Association Athletic Hall of Fame.
McShane was selected by the Dallas Cowboys in the 12th round (346th overall) of the 1976 NFL draft, with the intention of being converted into a linebacker.