Raised in Montvale, New Jersey, Hafley played prep football at Pascack Hills High School.
[2] Before entering the NFL ranks, Hafley spent 11 years on the collegiate sidelines with coaching stints at Worcester Polytechnic (2001), Albany (2002–05), Pittsburgh (2006–10) and Rutgers (2011).
While at Rutgers, the Scarlet Knights were the ninth-ranked passing defense in the country; Duron Harmon earned first-team All-Big East honors, and Logan Ryan received second-team accolades.
[6] On December 13, 2019, Hafley was hired to be the head coach at Boston College after the firing of Steve Addazio.
[8] On January 31, 2024, Hafley was hired by the Green Bay Packers to be their defensive coordinator, marking his return to the NFL after five seasons in the college coaching ranks.