He began his career as an assistant at UC Irvine, Santa Ana Valley High School, and Cal State Fullerton.

[1] Mathews began his coaching career in the 1972–73 season as an assistant at UC Irvine under Tim Tift.

In 1978, Mathews returned to Santa Ana Valley High to become varsity basketball coach.

In three seasons with Mathews as coach, Santa Ana Valley won two Century League titles.

[1] In 1981, Mathews returned to the collegiate ranks in his first NCAA Division I job, as an assistant coach at Cal State Fullerton under George McQuarn.

[1] During Mathews's four seasons on staff, Cal State Fullerton made the 1983 National Invitation Tournament.

Mathews led San Bernardino Valley to a 27–5 record in 2004–05 with the Foothill Conference title, then 24–12 in 2005–06.

In 2010, Mathews joined Ben Howland's staff at UCLA as an assistant coach.