Shizuka is a slender woman and has a similar appearance with her son, Hayato. She has short black hair in a pixie cut and narrow eyes with light colored irises. She wears earrings with a long-sleeved blouse and shirt.
She has a general laid-back and very easygoing personality. She has a large amount of patience when dealing with her talkative and misbehaving son, Taka, sometimes gazing at him as a loving mother would, but becomes assertive and angry when she is rubbed the wrong way especially by her teenager son, Hayato, or ex-husband, Taizou. She has a tendency of hitting Hayato on the head when he does something foolish or disagreeable. Like Hayato, she extends this treatment to Usaida at times when he's slacking off on the job.
She is an expert with children and finds both Kotaro and Ryuuichi to be cute and charming in particular, which she claims to be "unlike her own sons."
Shizuka met her ex-husband Taizou when he was her teacher in high school. When Shizuka ended up in the school's health office after fainting because of her lack of nutrition and eating, Taizou strictly and sternly forced her to eat a bento lunch he actually made for himself, saying that he thought her lack of eating was due to her wanting to possibly lose weight. Shizuka, feeling guilty about eating his lunch, offered for him to share it with her. She thought that his choice of having sweet tamogoyaki in his bento was an odd thing in contrast to his personality. This sparked Shizuka's romantic interest in Taizou. At some point after in their lives, the two married and had their first born son Hayato, but they divorced shortly before their second born son Taka was born (implied to be due to their clashing personalities), leading Hayato to resent him and refer to him as only his "birth father" while Taka has yet to learn his identity.
- She shares a voice actress with her son Taka.
- Her name "Shizuka" means quiet, even though she is loud and assertive.