Cast[]
- Mario as Jimmy Neutron
- Toad as Goddard
- Yoshi as Carl Wheezer
- Luigi as Sheen Estevez
- Peach as Cindy Vortex
- Daisy as Libby Folfax
- Birdo as Elke Elkberg
- Donkey Kong as Jimmy's Dad
- Candy Kong as Jimmy's Mom
- Funky Kong as Carl's Dad
- Tiny Kong as Carl's Mom
- Diddy Kong as Sheen's Dad
- Dixie Kong as Sheen's Mom
- Cranky Kong as Cindy's Dad
- Wrinkly Kong as Cindy's Mom
- Paper Mario as Happy Jimmy
- Baby Mario as Gloomy Jimmy
- Fire Mario as Funny Jimmy
- Ice Mario as Romantic Jimmy
- Tanooki Mario as Cool Jimmy
- Metal Mario as Hulk Jimmy
- Shadow Mario as Evil Jimmy
- Boom Boom as Evil Goddard
- Boshi as Evil Carl
- Mr. L as Evil Sheen
- Princess Shroob as Evil Cindy
- Shadow Queen as Evil Libby
- King Boo as Evil Butch
- Petey Piranha as Evil Ike
- Glooper Blooper as Evil Nick
- Tatanga as Evil Jimmy's Dad
- Captain Syrup as Evil Jimmy's Mom
- Pom Pom as Evil Mrs. Fowl
- Waluigi as Blix Strych
- Chunky Kong as Mr. Strych
- Cosmic Mario as Jimmy Negatron
- Dark Bowser as Herman
- Krunch as Sam
- Bowser as King Goobot
- Bowser Jr. as Ooblar
- Bowser's Minions as The Yolkians
- Peewee Piranha as Poultra
- Wario as Eustace Strych
- Kammy Koopa as Grandma Taters
- Roy "Bully" Koopa as Baby Eddie
- Ludwig "Kooky" Von Koopa as The Junkman
- Morton "Big Mouth" Koopa Jr. as Professor Calamitous
- Wendy "Kootie Pie" O Koopa as Beautiful Gorgeous
- Lemmy "Hip" Koopa as Tee
- Iggy "Hop" Koopa as Zix
- Larry "Cheatsy" Koopa as Travaltron
- Toadsworth as Jet Fusion
- Pauline as Betty
- Dr. Mario as Future Jimmy
- Dr. Luigi as Future Sheen
- Dr. Yoshi as Future Carl
- Dr. Peach as Future Cindy
- Mouser as Paul The Monkey (DNA Productions)