Miki is a kind motherly figure that cares about her family. She has long violet hair and violet eyes. She also has long fringes framing her face and messy-looking bangs, that her easily angered and harsh daughter, Kagami inherited. Miki has a young-and-beautiful appearance and a slim physique, despite the fact she has given birth to four daughters. She is also shorter than her husband, Tadao Hiiragi.
Most of the time Miki plays minor roles, she is only seen when the Hiiragi's are watching television and when the cast is spending time in the Hiiragi Household. Miki, like the rest of her family, is also a volunteer at the local Takanomiya Shrine next to their house. She is seen working at the shrine during the New Year's festival in Let's Go to the Festival. In Base of the Sun, Miki and Tadao leave for a cruise, but they return due a mistake on the date of their trip.
|Konata Izumi - Tsukasa Hiiragi - Miyuki Takara - Kagami Hiiragi - Ayano Minegishi - Misao Kusakabe - Yutaka Kobayakawa - Minami Iwasaki - Hiyori Tamura - Patricia Martin - List of Characters|
|Sōjirō Izumi - Kanata Izumi - Yui Narumi - Tadao Hiiragi - Miki Hiiragi - Matsuri Hiiragi - Inori Hiiragi - Yukari Takara - Honoka Iwasaki - Nanako Kuroi - Hikaru Sakuraba - Hinata Miyakawa - Hikage Miyakawa - Akira Kogami|
|Goldy - Cherry|
|Anime Only Characters|
|Minoru Shiraishi - Meito Anizawa - Daisuke Ono - Gotouza|
|Manga Only Characters|
|Kō Yasaka - Yamato Nagamori - Izumi Wakase - Fuyuki Amahara - Tamaki Yamanobe - Miku Busujima|