Principal Mike Callaghan continues to surprise the Xavier staff as more and more of his eccentricities are revealed, while he is still perhaps the most sensible and down to earth person at the school. He is effective and highly respected, maintaining order while generally running things with a hands-off approach. He'll reprimand a staff member (often Gerry) when necessary, but for the most part trusts his subordinates to do their jobs as they see fit. He's perhaps a bit more competitive than anybody knew, but reveals himself to be a sensitive guy who truly appreciates the close friendships he's developed with some of the more experienced Xavier staff over the years. His tendency to step back and avoid micromanaging his teachers allows him time to continue pursuing his bizarre and exotic hobbies while at work.