Grant O'Brien has been with Ryan Walters since 2018 at Missouri. Walters was in his first year as the sole defensive coordinator for the Tigers after sharing the responsibilities with DeMontie Cross for two seasons that season and O’Brien has been with Walters every step since on his way to becoming Purdue’s head coach.

After his successful stint with Missouri, Walters headed up to Champaign to become the defensive coordinator for Illinois. O'Brien followed him. The two helped lead one of the best defenses in college football last season and now embark on a new challenge together.

As Walters becomes a head coach for the first time, he brings a trusted assistant with him to West Lafayette. The former defensive analyst is also doing something for the first time, being a full-time position coach. O’Brien will lead the Boilermakers’ safeties in 2023.

“The unique thing about my relationship with Coach Walters is seeing him develop over the last three places we've been at," O'Brien said.

When the two first started working together in 2018, O'Brien realized the special traits Walters had. Six years later, those characteristics remain intact during a new chapter of his coaching journey.

"When you get in a room with him, you can tell he's got relationship skills to all levels. He has the ability to connect and, you know, he's a wise dude, and he's got information to give, and we're fired up to see him lead this program," O'Brien said.

Learning from Walters and his defensive back expertise has prepared O'Brien for the opportunity to run his own room and contribute to what Purdue hopes is an elite defense in West Lafayette next season.