A former two-time All-Big Ten selection at linebacker, Diaco played under the great Hayden Fry at Iowa. He spent time as a defensive coordinator at Central Michigan and Cincinnati, but his big break came when Notre Dame called.
From 2010-2013, Diaco would work as the team’s defensive coordinator and linebackers coach adding an assistant head coach title in 2012.
His units would average rankings of No. 19 in scoring defense (second only to eventual national champion Alabama in 2012 when Diaco would take home the Broyles Award for best assistant coach in college football) and No. 30 in total defense.