Disambiguation: not to be confused with Tomoko Kawase.
Tomoko Hayasaka is the mother of Yukari and Suguru with their unnamed dad.

She is seen as strict, commanding and overbearing. She is always disappointed in Yukari because, unlike her younger brother, she is not a prodigy despite having good grades in school. She scolds her daughter and sometimes slaps her when she doesn't reach her expectations and wants her to focus on school and not be bothered with normal teenage activities, but did not know that her making her daughter work hard will eventually lead her daughter to becoming a supermodel.

She tells her children that good grades and good careers were the most important things in life and they must reach those goals at all costs, and her son Suguru is the child who she is the most proud of and Yukari always tries to reach her mother's wishes but to no avail. But after Yukari gets into modeling and meeting George, not only does her demeanor and personality change her mother starts losing her control over her daughter as Yukari starts deciding what she wants to do with her life and she no longer cares about what her mother wants from her anymore and starts living for herself.

At the end of the anime and manga, it can be speculated that Yukari cut ties with her mother after she becomes a model so she can finally get away from her mother's controlling nature for good.

While Tomoko always demanded good marks from her daughter, it's hinted that she might also hold resentment and jealousy for her daughter since Yukari is very beautiful and when Yukari started modeling she became more bitter and upset with her daughter.

However it can be said that Tomoko soften her attitude when Yukari starts getting more work, bragging about her even with sales people.