MISSION — Sonny Detmer, a long-time Texas high school football and father to current Mission High head coach Koy Detmer, died Tuesday at his home in Somerset. He was 76.

Detmer coached varsity high school football across Texas for 35 years, making prominent stops at Mission High and later Somerset.

Sonny Detmer established himself as one of the winningest coaches in Texas high school football history and a quarterback guru, which started with the tutelage of his two sons: Ty and Koy.

Ty thrived under Sonny Detmer’s guidance at Laredo United South and San Antonio Southwest before accepting an offer to play college football at BYU, where he later won a national championship and the 1990 Heisman trophy.

At the same time, Sonny and Koy Detmer were shredding record books and redefining how high school football was played. The father-and-son duo used a revolutionary air-raid attack to put Mission High on the map becoming one of the earliest teams in Texas high school football history to embrace a pass-happy offense.

Sonny and Koy Detmer helped lead the Eagles to the Class 5A 1990 state semifinals in the Houston Astrodome, the farthest any Valley school has advanced in the UIL state playoffs since, by throwing for 4,829 yards.

Sonny helped Koy land an offer to play college football at Colorado and end his career as the most prolific passer for a single season in Texas high school football history. He also watched both of his sons play professionally.

The elder Detmer tallied a 68-32 record as head coach of the Mission Eagles from 1989 to 1997 when he later returned to the San Antonio area where he has coached at Somerset High School for more than two decades.

There, Detmer was able to tutor several of his grandchildren at quarterback as well including Texas A&M-Kingsville senior signal caller Koy Detmer Jr. and Koal Detmer, Somerset’s current starter at quarterback.

After his retirement from the NFL, Koy Detmer joined his father Sonny’s staff as an assistant coach before being hired to fill his dad’s old shoes as the Mission Eagles’ head football coach.

“I love Mission,” said Sonny Detmer in 2011 after a Somerset-Mission Veterans game, his official coaching return to the RGV. “It was really a great thing for me. It was one of the greatest experiences I ever had in my life (coaching in Mission) and this was another one.”

“It was great coming back down here to Mission. People are always great to us down here,” Koy Detmer said after that 2011 Bulldogs-Patriots matchup. “I consider it home. It was great getting down here and getting back on the field. It brought back a lot of memories.”

Sonny Detmer was inducted into the RGV Sports Hall of Fame in 2009 with 239 career coaching wins, making him one of the 50 all-time winningest coaches in Texas high school football history and the second-winningest Rio Grande Valley coach ever.

“Coach Sonny Detmer was my first boss back in 1990 and was a man that everyone loved,” said Mission Veterans head football coach David Gilpin in a Twitter statement. “(He was) a true mentor to so many. He will be greatly missed.”

Email: amcculloch@themonitor.com

Twitter: @ByAndyMcCulloch