[1] Wallace attended Central High School, where he developed into a three-sport athlete (football, basketball and track).
In football, he was a starter at nose guard, while contributing to the 1965 Class AAA state championship that beat Poudre High School 14-0.
He received Western Athletic Conference Player of the Week honors after posting 10 tackles, 3 passes defensed and one forced fumble against the University of Utah.
As a rookie, he was switched from the defensive to the offensive line,[4] becoming a member of the Super Bowl VI winning team under coach Tom Landry.
In 1972, he left abruptly during training camp after reporting 36 pounds overweight, stating that he was considering retirement, but went on to have a change of heart and returned to make the final roster.