Jake Collins (Nicholas Purcell) - The newest member of the Troop who is amazed to find out that monsters exist. He is shown to be quite a good artist who draws his own comic strips and reads comic books obsessively. Hayley and Felix often have to watch his back, because his instinct for danger often gets him into trouble. Hayley thinks he is a goofy slacker who doesn't take his job seriously. His worst fear is that he would not be able to help Felix and Hayley if they were in trouble and they would get hurt. Jake appears to have a slight crush on Hayley, though it is unknown if he's been able to admit this to himself, or if Hayley feels the same. However, the sparks the two occasionally share were enough to draw the Eris Fairy, a mythical creature that breaks up loving couples.
Hayley Steele (Gage Golightly) - The most popular, and often considered the friendliest, girl at school. She is the classic overachiever — she does cheerleading, plays lacrosse, has been in ballet since she was little, is in student council, and does numerous other extracurricular activities. She wants to go to Yale after high school, and is so into this vision that her favorite color is Yale Blue. She is very headstrong and, at one point, was ordered to take the weekend off of monster hunting so she could relax. Another sign of her workaholic nature is that, when faced with a monster that showed her her worst fear, she saw a room full of late homework assignments. Jake thinks she's extremely bossy and overbearing. She and Jake are good friends, but there have been several hints of something more. In the episode "Speed", she was hurt when he claimed he was just doing his job when he told her he would never leave her if "he ever got the chance" to be her boyfriend, which he seemed to be honest about in the moment.
Felix Garcia (David Del Rio) - The nerd of the school, Felix is complex. He is just dying to tell someone about his involvement in the group so he can be the "cool" guy, but because of his oath he does nothing. He sees himself as a type of James Bond within The Troop who Jake and Hayley look up to, but in reality they both think he is just a stereotypical nerd. Felix is an off-the-charts genius. An expert on mysterious creatures and paranormal activity, he's fully prepared to take on any monster, though he's scared of ghosts. He's also terrified of clowns, especially if they have beehive hands and lobsters for feet. Felix doesn't fit in at school, so The Troop are his closest friends. He fell for the Eris Fairy and was very disappointed when he found out she had a boyfriend back in her own dimension. She did kiss him on the cheek, however, and hints that that a cute girl in chemistry has a crush on him, but he still doesn't know which girl or which class.
Mr. Stockley (John Marshall Jones) - The school administrator and The Troop adviser he is undercover just like the kids. Mr. Stockley is The Troop's adult advisor, a job he takes very seriously. He keeps Jake, Hayley, and Felix up to date on recent monster activities, and makes sure they have the latest monster-fighting technology. However, when faced with a monster he panics, due to the fact that as you age you become less able to fight against monsters. His first name hasn't been revealed.involving electronics, it spontaneously malfunctions, usually either catching fire or falling apart (excluding his arcade games and mini-golf courses).
Gus (Chad Krowchuk) - A nerdy boy who is constantly picked on, but is known as one of the troop's worst nemesis, seeing that he can gain control of the most powerful monsters on the planet and use them for his own evil ways. He is the main antagonist of the series. He likes being called Augustus, but everyone calls him Gus, which thoroughly enrages him in later episodes as it reminds him of the troop. He loves Haley because she was the first to accept him and sees Jake as a rival. Despite the fact, The Troop tried to wipe his memory, he constantly evades them to the point he had to be locked away. He returns as the main antagonist for the series one finale when he attempts and succeeds at releasing every monster the Lakewood troop has ever captured, but he ultimately fails when his 'monster magnet' goes into overdrive and activates a portal to the monster world which he then enters rather than being captured and 'snarked'. it is unknown what happened to him, but sounds that came from the portal moments after he entered suggest he was attacked and mauled.
Phoebe Collins (Matreya Fedor) - Jake's little sister. She has shown in some episodes that she is destine to be part of the troop when she meets a dragon and was not afraid of it, also in a Halloween special she wasn't afraid when she thought Felix was in a monster costume, but it wasn't really Felix. She some times she shows that she doesn't care about Jake but really does care for him. In "I, Monster", she indirectly saved her brother. She called his cell phone, which rung inside the cocoon that Jake was held in and Hayley and Felix found out Jake was the monster.
Cuddy (Dejan Loyola) - Jake's friend who has appeared in many episodes.
Angie Crabtree (Brenna O'Brien) - A rather unpleasant girl who's a frenemy to Hayley. She claims to have no sense of humor and is the school news reporter.
Lance Donovan (Jean-Luc Bilodeau) - One of The Troop members that appears in "Tentacle Face" he is the most highly awarded troop member to date and spent years trying to capture a behemoth to gain the ultimate troop honor, but he soon became to old to fight monsters, (as they had begun to scare him) and Jake had to destroy the behemoth instead. he then becomes a troop leader so that even though he can't fight monsters he can still pass on his wisdom and not retire.
Bianca Stonehouse (Kyra Zagorski) - A world-famous troop leader that appears in "The Substitute". she was originally a locht in disguise but was freed by Jake and Hayley. she then helped them track down the lochts, but didn't help them fight as she is now terrified of monsters due to her age. inventor of the famous troop fighting move 'the stonehouse kick'.
The J-Troop - A troop from Japan, the J-Troop is a Japanese troop that includes Akira (Bernie Yao), the strict field leader who has a thing for Hayley, and the twins, Yuki and Keiko (Diana Bang), who are in love with Felix due to him being popular in Japan. Their only appearance is in "Lost in Translation" where they were sent both to train them to reach a higher level, and to trick them into thinking that they came to see a demonstration of how good the American Troop was.