Jiji is Kiki's companion as she is training to become a full-fledged witch. One time, he had to pretend to be a stuffed cat for a boy's birthday gift. The real stuffed cat, which looked exactly like him, was lost in the forest.
Jiji also gets a girlfriend, who is a white cat named Lily. In the credits, it is shown that Jiji and Lily had kittens together.
In the American version, Jiji is a chatty and sarcastic cat that likes to act proud whilst in the Japanese version, Jiji is a cautious and cute cat that acts humble and is always ready to help Kiki.
The character of Jiji is significantly different in the American dub. In the Japanese version, Jiji is voiced by the female performer Rei Sakuma, while in the American version Jiji is performed by Phil Hartman, and also has more of a wisecracking demeanor.
In Japanese culture, cats are usually depicted with feminine voices, whereas in American culture, their voices are more gender-specific. A number of Hartman's lines exist where Jiji simply says nothing in the original (such as in the scene where Jiji approaches Lily along the top of the wall). Jiji's personality is notably different between the two versions, showing a more cynical and sarcastic attitude in the 1998 English version, as opposed to cautious and conscience-like in the original Japanese.
Jiji is a black cat with large white eyes and black pupils. The insides of his ears are iris purple.
- In the original Japanese version, Kiki loses her ability to communicate with Jiji permanently but in the American dub a line is added which implies she is once again able to understand him. Miyazaki has said that Jiji represents the childish side of Kiki, and the reason why she loses her ability to communicate with him is because she has grown up.
- Jiji was Phil Hartman's last role before his death in 1998.