During his decorated collegiate career at Oklahoma, Casillas earned consensus All-American honors in both 1984 and 1985, along with first-team All-Big Eight recognition in those same years. His exceptional play in 1985 also garnered him the UPI Lineman of the Year and Big Eight Conference Defensive Player of the Year titles. He graduated with Academic All-American honors and a degree in public relations, laying the foundation for a professional career that would include two Super Bowl victories. Casillas immediately made an impact in the NFL with the Atlanta Falcons, earning a spot on the PFWA All-Rookie Team in 1986 as a nose tackle in their 3-4 defense, recording 111 tackles and a sack.
Casillas’s legacy will be further honored with his upcoming induction into the Oklahoma Hispanic Hall of Fame in 2025.