Prior to his time at Florida, Mattison coached at University of Notre Dame from 1997 to 2004 as the defensive coordinator under Bob Davie until the Ty Willingham era (during which he served as defensive line coach and recruiting coordinator).

Under head coach R. C. Slocum, the Aggies featured the "Wrecking Crew", a nickname for one of the nation's top-ranked defenses.

[1] He was the team's linebackers coach, a job he got in part due to his relationship with John Harbaugh.

On January 18, 2011, the Ravens announced that Mattison had accepted the defensive coordinator position at the University of Michigan.

His contract at Michigan made him among the highest paid college football assistant coaches in the country.

Mattison had served as the defensive coordinator and linebackers coach under Jack Harbaugh at Western Michigan from 1981 to 1986.