Butt-Monkey: His inventions usually cause troubles.Bungling Inventor: While he's undoubtedly a genius, the plots of most episodes are kicked off when his inventions go haywire.Breakout Character: During the time of the film and the early run of the series, Jimmy became Nickelodeons official mascot.In The N-Men, Jimmy spends pretty much the entire episode being bullied, ignored, and insulted by his so-called friends. He becomes so fed up, that he turns into a Hulk-like creature and terrorizes the town for revenge. This also happens when his insecurities are shown. Break the Cutie: He becomes a victim of this whenever something really bad happens to someone he deeply cares about.Brilliant, but Lazy: Why do something as simple as neatly put away your piles of pants when you can implant chips in them that do it for you? Carl and Sheen call him out on this, though.Subverted by the end when he saves them all and they appreciate him more, especially since he saves them from the new Neutron Black Sheep, Jimmy's cousin Eddie, who is just as intelligent, but villainous (and a baby.) Black Sheep: In "Clash of the Cousins," most of the Neutron extended family views him as such, correctly pointing out that, while Jimmy may have saved the day quite often, more often than not, it was one of his inventions that caused the problem in the first place.Big, Thin, Short Trio: The Short to Carl's Big and Sheen's Thin, although he compensates for his short stature with a combination of both his big skull and his tall, swirly hairdo.Jimmy: Not that! Anything but that! "NOOOOOOOOOOOOOOOOOO!" Another Cindy-related moment is when he finally succeeded in asking Cindy on a date, only then he realized what he'd done.When the show comes back on, Sheen and Carl comment that he had been screaming for four minutes straight. In a bit of Leaning on the Fourth Wall, the scream cuts to a commercial. In "The Tomorrow Boys", after learning he gets married to Cindy.Big "NO!": Whenever Jimmy comes to any shocking realization, you can bet the whole of Retroville will know about it instantaneously.
Arch-Enemy: He has made himself a lot of enemies but probably the three biggest examples are King Goobot, Finbarr Calamitous and Eustace Strych.
Despite living in a world where space aliens and alternate dimensions exist, Jimmy refuses to believe in magic and is convinced that the fairies and associated creatures in the Fairly OddParents universe are merely highly advanced computer programs.