Principal Irving Slimovitz is the principal at Norrisville High.
Slimovitz is a nervous yet overly optimistic principal. Although he's stuck in a school that's always dealing with monsters and robots, Slimovitz is always trying to deal with it and hopes that the school will be free of constant damage eventually. He is easily terrified whenever he gets attacked, failing to follow his own rules for the drill because the real robot scares him. However, he is at least fair, often giving kids detention if they break rules. He does find some crimes more annoying than others, though, saying the one thing that he despises more than tour abandoners are tattletales in "Randy Cunningham: 13th Century Ninja".
Slimovitz is tall and skinny with balding grayish-black hair and yellow-green eyes. He wears glasses, a white turtleneck shirt underneath a gray vest and brown jacket, grayish-blue pants, and black shoes.
Principal Slimovitz talks to Hannibal McFist, Bash's mother, and Bash Johnson about Bash's behavior. He gives the details of all of the times Bash bullied, someone. Bash's mother claims that she won't believe that he could ever do such mean things. Bash states that he was being framed. They then hear some kids saying that they saw the ninja. Principal Slimovitz then runs after them to see the ninja. His car seems to get constantly destroyed.
- A running gag in the series is that Slimovitz's car is constantly demolished, usually due to whatever monster or robot is battling the Ninja.
- Slimovitz usually talks to his students through a bullhorn, even if there's only one or two of them and they're standing right next to him.
- In "Gossip Boy", it's discovered by Randy that he likes to pretend to be a big baby cowboy after school.
- Slimovitz is the first adult to be seen stanked in the show in "Lucius O'Thunderpunch".
- In "Randy Cunningham: 13th Century Ninja", Slimovitz led an underground resistance to raid Charlie Cluckers after the Sorcerer escaped.
- Psycho-Bot learned despair from Principle Slimovitz.
- His first name is Irving, as seen in Evil Spirit Week.
- Slimovitz is the last character in the series to be stanked by The Sorcerer.
- In "The Prophecy of Hat Sword", it is revealed that he does not believe in prophecies.
- He has a cat.