John Costello was a beloved coach, teacher and mentor in Loudoun County Public Schools for 25 years. He served as a physical education teacher, golf coach, baseball coach, and boys and girls basketball coach. In December 2022, he tragically died in a car accident.

In 2005, 'Coach Cos' started the Special Education Adaptive Field Day at Broad Run High School. This year, the event was renamed Coach Costello's Field Day in memory of him. What started at one school has now expanded to six high schools in Loudoun County. He had, and his legacy continues to make, a profound impact on the school and community.