From 2002 to 2004, Grinch was a graduate assistant under Gary Pinkel at the University of Missouri, and he completed his master's degree in educational leadership and policy analysis at Missouri in 2004.[6]
New Hampshire
Grinch's first regular assistant coaching job was at Division I-AA New Hampshire under Sean McDonnell. In 2005 and 2006, Grinch was the cornerbacks coach.[6] After a promotion, Grinch became the recruiting coordinator and coached the entire defensive secondary in 2007 and 2008. Chip Kelly was the OC at New Hampshire and Grinch learned the value of practicing fast from competing against him every day.[7]
Wyoming
Grinch spent three seasons at Wyoming as the recruiting coordinator and coaching the secondary.[7]
Missouri (second stint)
Again working under Pinkel, Grinch coached the safeties at Missouri from 2012 to 2014.[8]
Washington State
From 2015 to 2017, Grinch was the defensive coordinator and secondary coach at Washington State under Mike Leach.[8]
Ohio State
In January 2018, Grinch joined Urban Meyer's staff at Ohio State as co-defensive coordinator.[9]
Oklahoma
In January 2019, Grinch joined Lincoln Riley's staff at Oklahoma as defensive coordinator.[10] He spent three years with the Sooners and was able to help a defense that finished 101st in scoring defense and 130th in passing defense, under former defensive coordinator Mike Stoops, who would be fired after giving up 48 points to rival Texas.[11]
USC
In November 2021, Grinch followed Riley after he was hired to be the next head coach at USC, serving in the same capacity as before.[12] At USC he inherited a Trojan defensive roster that in 2021 finished as one of the worst units statistically in program history, ranking 103rd in scoring defense and well below average in all other categories.[13] After a promising three game start to the year, the Trojan defense allowed 293 points over the next seven game stretch and fell to 7–3. Of these seven games, opponents scored over 41 points five times.[14] On November 5, 2023, Grinch was fired as USC's defensive coordinator.[15]
Wisconsin
In February 2024, Grinch joined Luke Fickell's staff at Wisconsin as co-defensive coordinator and safeties coach.[16]
Personal life
Grinch grew up in Grove City, Ohio and graduated from Grove City High School.[17] In 2003, he married Rebecca Blaser. They have two children.[8] He is the nephew of longtime Missouri head coach Gary Pinkel, under whom Grinch worked as a graduate assistant and safeties coach.[17]