John Walker is the principal of Metroville Elementary School.
During Dash Parr's immersion in Metroville Elementary, Bernie Kropp is always sure that he is playing pranks on him. Whenever Bernie suspects Dash, he is sent to the principal's office and his parents are called. However, Bernie has little evidence to convict Dash until he hid a camera but wasn't quick enough to record his superspeed. Everytime Walker lets Dash go.