Kyoko's father, known only by the family name Chigusa, is a minor but recurring presence in Maison Ikkoku. His first name is never given, and he is referred to by Kyoko as her father, by his wife as anata, and by everyone else simply as Chigusa. He comes from a comfortable middle-class background and works as a salaryman, embodying a conventional, respectable Japanese household head. Together with his wife Ritsuko, he raises Kyoko as their only daughter in a stable and loving family, even if that household is not without its arguments, particularly whenever the subject of marriage or Kyoko leaving home comes up.

In terms of personality, Mr. Chigusa is protective, proud, and somewhat old-fashioned. He is depicted as stubborn and meddling in family matters, and at times comes across as arrogant or domineering, though these traits are rooted in genuine concern for his daughter rather than malice. He was firmly against Kyoko's marriage to Soichiro Otonashi, her former high school teacher and a man roughly ten years her senior, and he never fully warmed to the match. After Soichiro's death so soon after the wedding, Mr. Chigusa and his wife hope that Kyoko will move forward with her life and eventually remarry. His caution extends to Kyoko's later suitors: while his wife Ritsuko is charmed by the polished and successful Shun Mitaka, Mr. Chigusa views Mitaka with suspicion, seeing him as a possible womanizer who could break his daughter's heart. This wariness reflects his deep protective instinct and his difficulty trusting anyone he feels is unworthy of her.

Within the story, Mr. Chigusa functions mainly as a background family figure who appears during visits and key family moments. He represents the conventional parental pressures that Kyoko must navigate, and his opposition to her choices, first to Soichiro and later in her romantic life, reinforces her independent streak. His role becomes a source of occasional friction and comedy, as his stubbornness clashes with Kyoko's equally strong will, but he never becomes a true antagonist. Rather, he is a caring father who wants security and happiness for his daughter in the way he understands it.

His key relationships are defined by this protective love. With Kyoko, he shares a close but sometimes tense bond, since she is determined to make her own decisions about love and work. With his wife Ritsuko, the two form a united, if often exasperating, parental front, though they do not always agree, as seen in their differing impressions of Mitaka. Toward Soichiro, he is a disapproving father-in-law who only reluctantly accepts the marriage. His attitude evolves over the course of the series: he gradually comes to trust Kyoko's judgment, and his eventual acceptance and blessing of her relationship with Yusaku Godai marks his development from a skeptical, controlling father into one who supports his daughter's happiness.

Mr. Chigusa has no notable abilities or special skills; he is an ordinary working man whose significance is purely familial and emotional. His value to the story lies in what he represents: the protective parent whose initial resistance and later acceptance help highlight Kyoko's growth as an independent woman and the importance of family approval in her eventual happiness.