Moreno, who is of Mexican descent, attended Castle Park High School in Chula Vista, California, and was a letterman in football and baseball.
[3] As a sophomore in 1994, Moreno helped Castle Park to a 12–2 record and a CIF San Diego Section Division II title with a 24–21 victory over Torrey Pines High School.
[4][5] On defense, he earned first-team All-San Diego Section Division II honors at linebacker, and on offense, he rushed for 272 yards and a touchdown on 52 carries at running back.
[7] As a junior, Moreno suffered a knee injury in Castle Park's Metro Conference championship game victory.
[11] Moreno was named the CIF San Diego Section co-Defensive Player of the Year and was selected to play in the California-Texas Shrine All-Star Game.