Haruka is a pretty normal person, but she is not very open to other people as shown when she didn't participate in the class's swimming session where she tends to prefer keeping to herself and not bothering people, simply to avoid trouble. In the light novels, she is shown to be overly-conscious and uncomfortable with several boys giving her attention, due to her large bust. As a result, she tries to avoid flirty boys. She speaks quite a lot but only with people that she is comfortable with such as those in the Ayanokōji Group. She also has a habit of nicknaming her friends, such as giving Kiyotaka Ayanokōji the nickname "Kiyopon" or "Ayanon" because they sounded cute, showing that she enjoys teasing others a lot. Even though she enjoys teasing her close friends, she is also shown to be be firm at times as was shown in Volume 1 of Second Year Arc, when she called "Kiyotaka" (despite her habit to call him Kiyopon) in a serious tone.[1] She is also shown to be a caring friend as she encouraged Airi Sakura to become bolder and attract Kiyotaka's attention by dawning the same revealing Bikini swimsuit as her. She took extra steps by confronting Kiyotaka and asking him what he thinks of her so that Airi doesn’t have to. She believes that the concept of love will elevate and develop Airi to become a better person, and questioned why Kiyotaka didn’t accept her even though he is aware of her feelings. She is aware and attentive to her close friends feelings, which Kiyotaka took advantage of by tasking her to take care of Airi's feelings once he decides to reveal his secret relationship, which will undoubtedly cause her a deep depression.