He played college football for the California Golden Bears and was selected by the Colts in the first round of the 1997 NFL draft.

However, when the NFL told Glenn that he would also appear in the 2006 Pro Bowl, they later informed him that he did not receive enough votes, and that he would be an alternate.

Glenn did end up participating in the 2006 Pro Bowl replacing the injured Willie Roaf.

On July 24, 2007, following winning Super Bowl XLI the season before, Glenn announced his retirement, saying he had lost his passion for football.

He pursued a Master of Business Administration in the Executive Education program at the Purdue University Krannert School of Management, and graduated in December 2012.