She is voiced by Tomoko Kaneda in the Japanese version of the anime, and by Jessica Boone in the English version of the anime.
Chiyo has skipped five grades to tenth grade (the first grade in Japanese high school) at the start of the series and is still at the top of the class. She is extremely smart and responsible for her age — for example, she was chosen by the other students to be the class representative. However, Chiyo-chan (as she is usually called) still has the naivety, desires, and fears of a child.
She is 10 years old when she first enters high school (and 13 by the time she graduates), but despite the age difference, she gets along with her older classmates. Aside from being seen as impossibly cute, Chiyo is a nice girl — a peacemaker who tries to stop any bickering and who is generous by nature. Her friends sometimes take advantage of her good nature and scholastic abilities. Her biggest weakness is that she is terrible at sports — she is not only five years younger than her peers, but small for her age — which leads to a lack of confidence because she feels she is a burden. Her March birthday parties are an annual celebration for the girls. Chiyo is closest to Osaka, who is most like her in naivety, and Sakaki, with whom she shares an interesting relationship: Sakaki covets Chiyo's small stature, cuteness, and warm relationship with her dog, Mr. Tadakichi, while Chiyo longs for Sakaki's height and imposing air. Chiyo and Sakaki also share the interest for cute things such as Neco Coneco toys. On the other hand, Chiyo does not get along very well with Tomo, who loves teasing her all too much, similar to Yukari. Osaka frequently daydreams about Chiyo's pigtails, imagining that they detach, speak, move on their own, are used to fly, control Chiyo's mind, or even cause her death if removed incorrectly. Her parents, who are never seen (not counting the strange yellow cat-like creature dreamed by Sakaki and Osaka that claims to be her father), are very wealthy. Despite her athletic ineptitude, Chiyo is a devoted fan of the Yomiuri Giants and once got into an argument about them with Tomo. She also has a player's signature in her possession. She loves cooking, and also enjoys cleaning because, as she says, it "makes everything nice". She is very proud of being a high school student and works tirelessly to live up to that status. In the manga, when seeing a movie with her elementary school friends, she proudly asks for the more expensive high school student admission rate. She also periodically takes a part-time job at a fast-food restaurant with Osaka, because she felt this is something a high school student would do — although some patrons were nonplussed at being served by a 10-year-old girl who could barely see over the counter. Ironically, the restaurant manager gave her the job because he thought that such a young girl must have a very poor family if she's looking for work. Admittedly, part of Chiyo longs for the carefree fun of being a child in grade school, something of which her high school life does not often allow her. Another part of her, however, desires a physical maturity that matches her academic status — and will make others take her seriously. Early senior year, Chiyo announces plans to attend a university in the United States where students who skip grades have done well. In consequence, she does not take the college entrance exams her friends must deal with. It also leads to some especially bizarre fantasies on Osaka's part, who imagines Chiyo as a kidnap victim, President of the United States, and the original of a series of tiny Chiyo-clones working in every airport. It is unknown whether she plans to return to Japan after her studies.
To be added
- She shares a traits with Bubbles from The Powerpuff Girls franchise.