Davis attended Olathe South High School in Olathe, Kansas, and was a student and a letterman in football, basketball, and track & field. In football, as a senior, he was a first team All-League selection and a second team All-Metropolitan selection.
Davis was a three-year starter for the University of Kansas, and finished his superb career with 238 tackles (20 tackles for loss) and 9.5 sacks. Don Davis graduated with a degree in Human Development in 1995.
He was signed as a free agent in 1996 season by the New Orleans Saints. Davis played with the Saints until the middle of the 1998 season when he was traded to the Tampa Bay Buccaneers. He would remain with Tampa Bay through the 2000 season. In 2001 Davis began play for the St. Louis Rams, where he would remain through 2002. Then in 2003 Davis was signed by his final team, the New England Patriots, who he would stay with for four seasons. He earned 2 super bowl rings with the New England Patriots.
Following the 2006 season, Davis retired and joined the Patriots' strength and conditioning coaches as an assistant coach. He left the organization prior to the 2008 season to pursue Christian ministry. He remained with the Patriots as the team chaplain.