The former Michigan defensive coordinator under former coach Brady Hoke, has agreed to coach the defensive line next season for the U-M football program.
"I am very excited that Greg will remain here in Ann Arbor to continue coaching at this outstanding University," Harbaugh said. "He is a coach of the highest caliber who has dedicated his life to molding young men into outstanding people. He has strong bonds with our players and within this community. I have known Greg for a long time, and am so pleased that our relationship will continue here at Michigan."
Mattison has family ties to the Harbaugh family. He had previously coached under Jim’s father, Jack, and his brother, John, at Western Michigan and the Baltimore Ravens respectively.
"Michigan is a special place to me, and I am excited to be a part of Jim's staff," Mattison said. "This University and this community mean a lot to me and my family. Having the opportunity to continue coaching a group I've grown so close to is very special. I look forward to continuing my work with these young men."
As Michigan’s defensive coordinator the past four seasons, Mattison’s defense ranked top 20 nationally in total defense three times. In 2014, Michigan tanked seventh nationally in total defense (311.3avg.) and ranked 15th in rush defense (117.7 avg.).
Mattison previously coached the Michigan defensive line from 1992-96, and served as U-M’s defensive coordinator from 1995-96.