Cornish attended Chicago's Mount Carmel High School where he played at a middle linebacker as a freshman.
In 1991, he suffered a sprained ankle in minicamp, that allowed Courtney Hall to pass him on the depth chart and he was relegated to a backup role, seeing action mostly as the team's long snapper.
[4] On April 2, 1992, the Dallas Cowboys signed him as a Plan B free agent, reuniting with his college quarterback Troy Aikman.
[5] While starter Mark Stepnoski was involved in a contract holdout during training camp, he started throughout the preseason and for the first 2 regular season contests, becoming the first African-American center to make the team in franchise history.
Cornish replaced him in three games, until he was passed on the depth chart by John Gesek for the Playoffs and Super Bowl XXVIII.
[14] His father Frank Cornish, Jr. played defensive tackle in the National Football League for the Miami Dolphins and the Chicago Bears.