He is voiced by Kenji Nojima in the Japanese version of the anime, and by Brad Swaile and Greg Ayres in the English version of the anime.
Keisaku is a young boy with light-brown hair that goes down to his neck. He has a fair complexion and dark blue violet pupils. He is 15 years of age. In the anime, he is 167 cm tall. In the light novels he is described as being handsome.
Keisaku has a very different personality in the anime than he does in the novels. In the light novels, Keisaku is cheerful and sociable, often livening up his friends and setting the mood of the classroom. He is also friends with Yuji and Ike from the beginning of the story.
In the anime, Keisaku is more standoffish and has a reputation for being rough, more so during his junior high school days before becoming calmer after he began to hang out with Eita. He gradually becomes more sociable with Yūji and the others.