White first appears after Ben is harassed by Cash and JT who have vandalized the inside of Ben's locker with ABC chewing gum. Annoyed, Ben cleans up the gum and throws it at Cash. The latter ducks, and the gum instead hits Principal White in the face. Deceptively incensed, White gives Ben detention. Later, when it is revealed that he is a Plumber (to Ben's disbelief), he apologizes to Ben for the reprimand as it was part of his cover.
When Ben, frusterated about Eon, goes to the school gym to be alone, Principal White attempts to calm Ben's fears... offering to be a sounding board for his frusterations. White is about to leave just when Eon strikes again and shoves him aside. This time, Ben is able to become Diamondhead (voiced by Daran Norris) and fight him off. White is then laid up in the nurse's office.
When Eon tries to activate the Hands of Armageddon, Principal White gets out of the nurse's office and finds the imprisoned Plumbers. When trying to find the key to that room, they point to the button near the door which freed them all.
In the movie, White is played by Robert Picardo, known famously as the Emergency Medical Hologram (The Doctor) in Star Trek Voyager.