Jimmy has an energetic personality. He has a habit of saying "You rock and you rule!" ("OK! Perfect!" in the original Japanese version) to his Pokémon and giving them a thumbs-up after winning a battle. He can be quick to jump to conclusions but also knows when to be serious and get the job done.
Jimmy cares for his Pokémon very much, and he was determined to protect Raikou from Hun and Attila's scheme. Jimmy doesn't mind losing a round, as he is driven to learn as much as he can.