|Relatives:||Grandfather: William Shortpaws|
Sister: Thea Stilton
Nephew: Benjamin Stilton
Niece: Bugsy Wugsy
Cousin: Trap Stilton
Geronimo Stilton is the title character in the Geronimo Stilton book series. He is a very nervous and scaredy mouse. He also hates Halloween, probably because he is scared of it. He loves Cheesy Chews. Geronimo is allergic to cinnamon, and he fears cats the most.
Born in New Mouse City, Mouse Island, Geronimo Stilton is Rattus Emeritus of Mousomorphic Literature and of Neo-Ratonic Comparative Philosophy. For the past 20 years, he has been running The Rodents Gazette, New Mouse City´s most widely read daily newspaper.
Stilton was awarded the Ratitzer Prize for his scoop on The Curse of the Cheese Pyramid. He has also received the Andersen 2000 prize for personality of the year. One of his bestsellers won the 2002 eBook Award for world´s best ratlings´ electronic book. His works have been published all over the globe. In his spare time, Stilton collects antique cheese rinds and plays golf. But what he most enjoys is telling stories to his nephew Benjamin.
- Geronimo has an additional a niece. Her name is Bugsy Wugsy, even though it wasn't explained how she became Geronimo's niece. To become his niece, he has to marry Petunia Pretty Paws, which he is afraid to admit he wants to (He almost admitted in Save the White Whale, but was too nervous that he said he only got seasick).
- In Race Across America, Geronimo's home address written on his package tags were 8 Mouseford Lane, 13131 New Mouse City, Mouse Island.
- It is known that Geronimo is adopted, as explained in Kingdom of Fantasy II. In the 2004 book La vera storia di Geronimo Stilton, it is mentioned that Geronimo doesn't know who his actual parents are, and that he was adopted by the Stiltons when he was at infant age.
- Because of this fact revealed, the relationship status of his closest family members are questioned. We don't know if Thea is Geronimo's biological sister, if Benjamin is his biological nephew, or if Trap is his biological cousin.
- In the books, Geronimo wears glasses. In the show, however, he doesn't wear glasses.
- In the July 2012 book This Hotel is Haunted!, Geronimo seems to be a bigger fraidy' mouse than the other books. When he gets scared then Hercule Poirat laughs and Geronimo says "I CAN'T TAKE IT ANYMORE!".
- In the show, Geronimo seems to be somewhat braver than he is in the books.
- In mini book 2: The Lake Monster, it is revealed that Geronimo has a goldfish named Hannibal
- In Fabumouse School Adventure, Geronimo is known for his Agility and Athlectics due to his gymnastic Training for about one time.
- In The Way of the Samurai, Geronimo takes lessons in martial arts.
- In The Giant Diamond Robbery, Geronimo was accepted into the MISSO (Mouse Island Secret Service Organization) as an operative with the codename OOG. Despite that, he has never mentioned anything about running a spec ops mission or even working for the agency in later books.
- He even mention this line in the ending: "So far, I haven't had any cases like The Giant Diamond Robbery. But when I do, I'll be sure to fill you in. Mouse's honor!"