Despite being human, Jimmy seems to prefer the Underworld instead of the Human World, and is one of the few humans who ever visited Scare School. In "A Real Little Monster", Casper took Jimmy to Scare School to protect him from Norman. To stay unnoticed, Jimmy disguised himself as a creature named Jimbacca. Since the teachers of Scare School thought him to be a rare, supposedly extinct kind of creature, Jimmy quickly gained respect from both the students and staff of Scare School, and much to Casper's dismay since Jimmy wanted to stay at Scare School forever.However, Jimmy's cover was blown when his costume was accidently thorn apart, and he had to flee from Scare School again. laughter, so that he and Casper would win the Grimly Trophy. In "Power Outage" he helped the students of Scare School figure out Razznik's weakness and come up with a plan to defeat them. He even defended the now powerless students from his father, who wanted to capture them. However, Jimmy also frequently needs help himself, like when his dad wanted to move.
In season 2, Jimmy got to experience what being a ghost was like, when an accident with a projector turned him into a ghost.
Jimmy is smart, friendly, sweet, nice, kind, caring, funny, brave and helpful, although he can also easily be scared from time to time, and has a completely different attitude towards Norman who often bully him at school, but other than that he's a real sweet heart. He keeps his friendship with Casper, Ra and Mantha a secret for his parents, especially because his father is a Creature Catcher.
Jimmy has short golden blonde, bright blue eyes and light skin. He wears a blue and dark blue striped t- shirt, beige pants and grey sneakers.