Kikuko Kusanagi, a 34-year-old stay-at-home mother, manages household duties and cares for her family. She is married to Tōjirō Kusanagi and has a biological son, Tom, alongside adopting Mikan, an anthropomorphic cat. Her responsibilities extend beyond her immediate household when she temporarily leaves home to care for her own sick mother. Kikuko experiences a personal fear of heights.

In the manga adaptation, her marriage to Tōjirō is portrayed as harmonious and conflict-free, marked by mutual understanding. This stable relationship garners admiration from Kyōko, a girl Tom likes. Conversely, the anime adaptation depicts a moment of marital tension when Tōjirō arrives home late, prompting Kikuko to withhold dinner preparation in frustration, highlighting situational stress unique to that version.

Kikuko later gives birth to a daughter, though this child remains narratively peripheral. Her background lacks extensive elaboration across official media, with no significant development or expanded backstory beyond her core familial interactions.