Kazuo Kinoshita is a supporting character in the anime Rent-A-Girlfriend, where he appears as the father of the protagonist, Kazuya Kinoshita. He is a middle-aged man with a stern and serious appearance, characterized by his frizzled, graying hair and a pair of large half-rimmed glasses. His typical attire consists of conservative clothes suitable for a man of his age, and his expression is often fixed in a grave or serious look, though this can change quickly, especially in situations involving his mother, Nagomi.

In terms of personality, Kazuo is portrayed as a man of few words. By his son's own admission, when he does speak, his comments are usually important and carry significant weight. He appears to possess a strong moral code and a firm sense of propriety, and he is not afraid to express disapproval when he feels his son has acted in a way that is inappropriate or lacks conviction. This directness extends to physical discipline on occasion, as he will scold and lightly punch Kazuya to make a point. Despite his somewhat intimidating and abrupt exterior, he shares a fundamental trait with his son: an awkwardness in expressing affection. He can be easily excited or clumsy when showing familial love, which has led to moments of misunderstanding or drunken outbursts on special occasions like Kazuya's birthday.

His role in the story is primarily as a secondary family figure for Kazuya. He lives with the Kinoshita family, running the convenience store that now occupies the site of their former family sake shop. Through family events such as New Year's greetings, birthday parties, and trips to a family hot spring, he provides a quiet but grounding presence. While he is often in the background, his reactions create some of the series' comedic tension. For instance, after witnessing Kazuya handing money to Chizuru Mizuhara, he harbors a long-standing, vague suspicion that their relationship might not be what it seems, leading to meaningful, lingering glances at the couple during family gatherings. His relationship with his son is characterized by blunt honesty and a desire for Kazuya to mature and take responsibility for his actions. On the other hand, his relationship with his wife and mother is one of deep affection, even if he struggles to articulate it, which often puts him in the position of being caught between Kazuya's deceptions and the family's expectations.

Kazuya Kinoshita does not undergo significant character development as a primary protagonist would; rather, his role is to act as a consistent moral anchor and a secondary source of familial pressure on his son. He is the embodiment of traditional, no-nonsense fatherhood within the series. Regarding notable abilities, he does not possess any special skills or powers. His significance comes from his ability to see through superficial appearances due to his pragmatic nature. His most notable characteristic in the narrative is his skill at creating a tense atmosphere with few words, which often pushes Kazuya into more complicated situations to cover up his rental relationship with Chizuru. He is also noted to be 174 centimeters tall.