As assistant coach for the past three years, Armijo worked closely with the team's pitchers and catchers to improve their performances on the field. He participated in weekly scout meetings to help identify opponent weaknesses, strengths and tendencies. He also assisted with the team budget and travel arrangements throughout the year.

Since coming onboard as pitching coach, Armijo improved the pitchers' ERA from 3.87 to 1.99 and 96 to 161 strikeouts.

Before OLLU, Armijo coached and directed the After School Programming for Keystone School in San Antonio from 2008-2017. He was the head coach for baseball, junior varsity coach for basketball and strength and conditioning coach for soccer. In addition, Armijo coordinated and facilitated 11 after-school programs for up to 164 lower-school students and was the director of middle school after-school programs for up to 130 students.

Armijo has been a coach and player for the San Antonio Compadres men's fast pitch softball team since 1994.