He is friends with Makoto Tachibana, both being in class 1 together at their school, Nagisa Hazuki, who transfered to their school, and Rei Ryugazaki . Despite being friends in earlier years, Haruka and Rin Matsuoka are now rivals upon his return to Japan. They used to be in a swimming club when they were younger (with the exception of Rei), though after the departure of Rin, they didn't see much of each other with the contribution of the swimming club shutting down. Haruka and Makoto remained friends however.
Haruka, along with Makoto and Nagisa, starts up a swimming club within the school, in hopes that they may be able to return Rin to his old self. Haruka becomes the vice-captain.
Haruka is a fairly tall teenage boy, having an excellent physique, being exceptionally fit and well toned. He has straight black hair and blue eyes. He generally isn't seen smiling or showing emotion, almost always shown to have more of a stoic expression on his face.
He is a bishonen character, much like the rest of the main male cast.
Haruka is quite a stoic person, rarely seen expressing all that much, mostly seen with an aloof and impassive expression. He is quieter than his friends, seen as the strong and silent type. However, he cares a lot for his friends, and always notices the feelings of others even if he seems like he is not paying attention. This was shown when Haru noticed Makoto's fear of the ocean first.
He, Makoto, Rin, and Nagisa befriended each other and soon became best friends in elementary school. They competed in and won a relay together just before Rin left and buried the trophy in a time capsule at their swim club. During the winter of his first year in middle school, he beat Rin in a freestyle race and after seeing how devastated Rin was, he quit competitive swimming the end of that year.
- Haruka was nicknamed "Tsundere" and "Tsun" by members of the fandom before his official name was revealed due to his cold looking demeanor, which is often assosiated with tsundere characters.
- Haruka loves to eat mackerel.
- Whether Haruka is taking a bath, going to school or strolling casually, he always seen wearing his swimming trunks. He usually wears only an apron and his swimming trunks while cooking.