|Name in Japanese||高坂 大介|
|Romaji Translation||Kōsaka Daisuke|
|Debut (Anime)||Episode 01|
|Debut (Light Novel)||Volume 01 (Chapter 01)|
|Appears in||Light Novel, Anime|
|Voice Actor (Japanese)||Fumihiko Tachiki|
|Family|| Yoshino Kousaka (Wife)|
Kyousuke Kousaka (Eldest Son)
Kirino Kousaka (Youngest Daughter)
He is voiced by Fumihiko Tachiki.
Known to Kyousuke as a man with the appearance of a Yakuza member and the aura of a gorilla, Daisuke is a middle-aged man with tanned skin, swept-back hair and a face with well-defined features. He also sports a menacing glare behind the frameless eyeglasses he wears. When at home, he is always dressed in a traditional Japanese yukata and is occasionally seen drinking sake, especially to calm himself down in a tense situation.
Daisuke is a very strict parent to Kirino and Kyousuke, especially towards the younger sibling Kirino. He only allowed Kirino to be a model in a condition that Kirino must maintain her good performance in school. He also has a negative outlook on the otaku culture, believing that it is a good-for-nothing hobby and a bad influence. Despite these, Daisuke is appreciative and caring to Kirino, and he has been keeping pictures and articles of all of his daughter's accomplishments. Originally, Kyousuke thought his father didn't keep any pictures of him, though he later learned that Kirino stole those and kept them in her own private album.
Behind his scary face and attitude is a loving and supporting father. Aside from capturing the moments of her children's achievements on a camera he bought for himself, he also springs into action whenever something involving Kirino happens, especially during Kirino's sudden decision to throw away her otaku merchandise during her short stay in America. He is also quite distrustful of any male friends who try to win over Kirino's heart, and even planned on attacking Kouki Mikagami when he thought he was Kirino's boyfriend.
Daisuke also cares deeply for Kyousuke and trusts him with Kirino and believes he could protect her. He was willing to temporarily kick Kyousuke out of the house with the condition that he could only return if he had an A in his mock exam at the university he applied to, because he believed that the boy was able to get the grade. He also showed that he wasn't fooled about Kyousuke's lie of owning eroge and only allowed Kirino to keep her hobby because of his trust in Kyousuke.