Simpson is in his 16th season with the Rustler cross-country program. During his tenure at Golden West, Simpson has had several athletes go on to participate at the Sate Championships. In addition to working with the Rustler harriers, he has breathed new life into the Rustlers track and field program. In 1999, Simpson received Orange Empire Conference Coach of the Year honors as he guided the Rustlers to a 7-2 dual meet record.

Before joining the Rustler staff, Simpson coached at Fountain Valley High. He led the Barons to a 30-1 dual meet record and four Sunset League titles and four CIF finals berths in as many seasons (1987-90).