Harry Herpson High School first appeared in the "Pilot". Rick told to his daughter and son-in-law how he thought school was worthless and a waste of time and that Morty shouldn't be forced to keep going there, and instead just stay home with him, much to the disapproval of Jerry and Beth. At school, during Mr. Goldenfold's math class, Morty remained distracted by Jessica (his classmate) and was staring at her longingly. He then fell asleep when he was taking a test and ended up fondling Mr. Goldenfold in his sleep.
Later, he was walking through the hallway, when confronted by a bully named Frank Palicky, who attempted to kill him, but was stopped by Rick when he froze him with his freeze ray and took his grandson Morty out of school. Beth got a call from Principal Vagina, and so she and her husband Jerry visited the school for a meeting with him, where he told her that because of Rick, their son Morty has only attended seven hours of school over the course of two months. Rick and Morty eventually returned to the Dimension C-137, and ended up in the lunchroom. Jessica and Morty started to have a conversation, before Rick pulled him away, only to be stopped by Morty's parents and Principal Vagina.
In "Lawnmower Dog," Rick brought up the statement again, that school is worthless and is actually a burden on Morty's learning process. He still helped Morty implant Mr. Goldenfold's mind, to make him give him an A at math, to get his parents off of his back about what he's learning there.
Harry Herpson High School briefly appeared in "Meeseeks and Destroy," where Summer used her Meeseeks to convince everyone to elect her school president. There was a huge ceremony in the gym where he made the speech and she officially won the election and became the most popular girl at school. Principal Vagina also asked for help with his divorce from Mr. Meeseeks, but he vanished, having already completed his assigned task, leaving Principal Vagina sad and alone.
In "M. Night Shaym-Aliens!," Rick was trapped inside of a giant simulation of the real world. One of the simulations was of Morty going to Harry Herpson High School. Morty's hologram was so realistic while the holograms of everything else were so fake. In the simulation, Morty's hologram was in Mr. Goldenfold's "math class" and he asked a simple math question that no one could understand except Morty. Everyone thought Morty was a genius for getting it right and Jessica's hologram was even going to ask Morty to be his boyfriend, before Rick pulled him into the boy's locker room to talk about the simulation. They took off their clothes in the shower, in order to get the aliens to not watch them while they talked about it.
In "Rick Potion #9," where the school was holding a flu-themed prom and Morty wanted to ask Jessica. He started to talk to her but then Brad butted in and told him off for talking to a girl who was out of his league. Morty later got Rick to make a love potion for him to use on Jessica but Rick forgot to warn him of the side effects of using it on someone who had the flu. When he got to the prom, he used it on Jessica, only for the flu virus to make the love potion go out of control, and make her become madly in love with him. The love potion piggy-backed the virus then spread to all of the other students and faculty at the school. Brad, Principal Vagina, Mr. Goldenfold, and Morty was eventually chased out of the school from all of these people.
In "Total Rickall," Morty had a flashback of all the horrible moments he's had with Rick. One of them was when he was at school, and Rick pulled down his pants, making him fall down a flight of stairs and crash into the ground in front of two girls, who laughed at him, along with Rick, making him cry.
In "The Ricks Must Be Crazy," in a post-ending credits epilogue, Morty was in Mr. Goldenfold's math class, falling asleep because of how bored he was, when all of a sudden, he transformed into a car in the middle of class. This was a brick joke from an earlier scene in the episode.
In "Morty's Mind Blowers," Morty thinks that he sees Mr. Lunas threaten him on the moon while looking at it through a telescope. Mr. Lunas is, in fact, a real person who does not live on the moon, as he comes to Morty's high school to work as a guidance counselor. Later on, Morty snaps pictures of Lunas, planting an American flag in his yard, and tells Principle Vagina that he thinks Lunas is "up to something" and "lives on the moon." Vagina takes this as a metaphor for pedophilia, and goes outside to the parking lot to confront Lunas, ending in Lunas getting punched in the face, and later killing himself.
- Morty Smith
- Summer Smith
- Toby Matthews
- MC Haps
- Jessica's Friend
- Kelsey Shawsen
- Katherine Heffelfinger
- Tricia Lange
- Christina LaCroix (C-132) (comic only)
- Steve Graynor (comic only)
- Frank Palicky - Deceased
- Tiny Rick - Expelled; Deceased
- Tammy Gueterman - spy for the Galactic Federation, Long Story
- Bullies - Deceased
- Mr. Poopybutthole (different universe, graduated)
- Lawnmower Dog (mentioned)
- Meeseeks and Destroy
- Rick Potion #9
- M. Night Shaym-Aliens! (hologram)
- Pickle Rick (mentioned)
- Rest and Ricklaxation
- Morty's Mind Blowers
- The ABC's of Beth
- The Rickchurian Mortydate (mentioned)
- Morty's math class is the only class that is ever shown. It is also the only class that is even mentioned, except for the gym class taught by Coach Feratu which was only mentioned in one episode.
- We know that Mr.Poopybutthole attended his universe's version of Henry Herpson.