In Episode 65 of Coaches at Crown Brew Getting Coffee — presented by the Swinford Media Group and sponsored by Adrenaline Fundraising, Marion Plumbing, and Swinford Wedding Photography and Videography — host Kerry Martin sits down with Carterville Athletic Director and Head Football Coach Brett Diel, one of the most accomplished and respected multi-sport coaches in Southern Illinois.

A Carterville native and member of the Lions’ 1996 state championship football team, Diel’s career reflects a deep connection to the program and community that shaped him. After earning his degree from the University of Illinois, he began his coaching journey at Unity High School under legendary coach Scott Hamilton, where he developed a detailed understanding of scheme, teaching, and preparation that would define his coaching philosophy.

Diel later returned home to Carterville, spending 14 seasons as a classroom teacher and defensive coordinator under Dennis Drust. During that stretch, the Lions captured eight conference championships, made 26 playoff appearances, and reached five quarterfinals, with Diel earning recognition as one of the area’s premier defensive minds.

Beyond football, Diel built one of the most successful softball programs in school history. From 2003 to 2015, he guided Carterville softball to a 342–106 record, seven conference titles, five sectional championships, two Elite Eight finishes, and the 2008 IHSA state championship. His work across multiple sports established him as a program builder focused on culture, accountability, and sustained excellence.

Since taking over as head football coach in 2019, Diel has continued Carterville’s tradition of winning, compiling a 50–18 record with three conference titles, multiple playoff runs, and a 9–0 regular season in 2025. Now serving as Athletic Director, he oversees an athletic department defined by consistency, development, and community pride.

Kerry and Diel dive deep into the craft of coaching — from lessons learned as a player and young assistant to adapting schemes to personnel, emphasizing football intelligence, and building trust within a staff and locker room. Diel reflects on mentorship, preparation, leadership, and the balance between confidence and humility required to sustain success over time.

In this thoughtful, wide-ranging conversation, Diel offers insight for coaches, parents, and athletes alike, emphasizing preparation, accountability, and relationships as the true drivers of winning programs. It’s a candid look at leadership, longevity, and the responsibility of guiding the same program that once guided him — from championship player to head coach and Athletic Director.