Naoko is a middle aged woman of average height.
She has brown eyes along with shoulder length brown hair which she ties into a sideway ponytail with an orange ribbon. Naoko is described to have an evil gaze which makes her seem like a careless person.
Despite having an evil gaze that makes her look like she's in a bad mood, Naoko is actually the type of person that doesn't really think of anything, and her compassion toward others is generally off the mark and irrelevant; however, she always prioritizes her son Subaru. Both Kenichi and Subaru agree that she is the most slow-witted person in the world at least on the surface, but later in Subaru's trial Naoko shows she is more perceptive then she appears. Like her husband, she is a mayonnaise lover.
At some point, Naoko married Kenichi and had a son with him; Subaru. Naoko would take notice of how her son idolized his father and wanted to be like him. However, after this proved to be impossible, he went through a downward spiral that ultimately resulted in him becoming a shut-in. While the self-hating Subaru wanted his parents to reprimand him, the couple saw that their son was just going through something and instead subtly encouraged him to go back to school every day.
According to the author, after Subaru went missing (was transported to Lugnica), a police investigation was launched but ended up empty-handed. As a result, Kenichi and Naoko now spend their days praying for their son's safety.
- Naoko dislikes all small and round foods such as peas.