He is the Mexican-American junior commissioner of the X Middle School Safety Patrol. Once a regular patroller (much like Fillmore) Vallejo is a strong, supportive and rather strict leader, although he does usually show a softer side. Vallejo's catchphrase is yelling "FILLMORE!", which he does in almost every episode when he hears of something Fillmore broke, like a waxer, and ordering expensive walkie-talkies by tricking him in to signing his signature.