Mitsuya is a good-looking boy that is commonly described as an "Ikemen" with short blonde hair and brown eyes. In the manga, he also appears to have 2 piercings on the left ear.
He is usually seen is the school uniform but when outside of school can be seen wearing a cream colored fedora with a yellowish strip, a blue long shelved cotton jersey and a brown 3/4's.
Takanashi was initially snobbish, deceptive and arrogant to the point of ruining Hikari Tsutsui reputation just so he could have a chance with Iroha Igarashi by spreading rumors that Hikari was a lolicon. Later though, after witnessing the gravity of his actions, he begins to feel a bit of remorse and eventually apologizes to Hikari's family along with his younger sister who assisted him with this act. He eventually begins to tag along with Hikari and his group of friends more. He begins to act more like a friend to Hikari as the story progresses and starts to care more about Arisa Ishino, although he continuously denied it that this hints he is having feelings for her and plays into the "tsundere" trope.
Hikari is Mitsuya's greatest rival that he eventually started rumors spreading that Tsutsui is a lolicon due to his jealousy.
Arisa is Mitsuya's girlfriend.
In Season 2 Episode 12, he later becomes her husband and he becomes the father of an unnamed baby boy.
- Mitsuya's surname Takanashi means "tall, high" (高) (taka) and "pear" (梨) (nashi).