[4] During that time, Mount Union amassed a record of 54–1 and won three NCAA Division III Football Championships.
[5] Grinch's first regular assistant coaching job was at Division I-AA New Hampshire under Sean McDonnell.
Chip Kelly was the OC at New Hampshire and Grinch learned the value of practicing fast from competing against him every day.
He coached several NFL players including: Jalen Thompson, Daniel Ekuale, Frankie Luvu, Hercules Mata'afa, Destiny Vaeao, Xavier Cooper, and Shalom Luani.
[7] In January 2018, Grinch joined Urban Meyer's staff at Ohio State as co-defensive coordinator.
Oklahoma won the Big 12 championship and advanced to the College Football Playoff semifinals in the Peach Bowl.
Tuli Tuipulotu was named the Pat Tillman Defensive Player of the Year and unanimous All-American in 2022.
After a promising start with USC, the 2023 Trojan defense would later allow 293 points over the next seven game stretch and fell to 7–3.
[13] He coached several NFL players at his time at USC which included: Calen Bullock, Mekhi Blackmon, Solomon Byrd, Ralen Goforth, Shane Lee, Brandon Pili, Tuli Tuipulotu and Christian Roland-Wallace[14] In February 2024, Grinch joined Luke Fickell's staff at Wisconsin as co-defensive coordinator and safeties coach.