Usagi's mother is a quirky, active and extremely outgoing (even more than Usagi) woman. She enjoys cooking new recipes, exercising and taking care of Usagi and Shingo. She changes her hairstyle almost every day and is constantly trying out new omelet recipes. Even though Usagi and her mother get into fights, they love each other very much. Like any good mother, Ikuko worries about Usagi's grades and even sent her to cram school once. Mama is fairly observant about her daughter, she has a good knowledge of all her friends and acquaintances, and is good humored about Usagi's quirks. She was even friends in high school with Minako's manager, and they were big participants in their school's theatre program. He assisted her in creating a video to the talent agency in America.
Shingo is Usagi's extremely cynical brother. He dislikes much of what his crazy sister and mother do, and he attempts to ignore them whenever possible. He occasionally teases Usagi like an average little brother. He seems no to care much about of life in general. In fact, he even discovers Luna's true identity and reacts to it just like he does to everything: ignores it and goes back to playing his video games. He also helped out, apparently not entirely intentionally, with the video his mother made to send to an American talent agency.
Even though being mentioned by others, Usagi's father Kenji was almost completely absent throughout the series. He only appeared in the Special Act to attend Usagi's wedding, in tears.
While Ami's mother is largely absent from most of the series, she is a successful doctor who works at the Juban Secondary General Hospital. Most of her shown interaction with her daughter is using a dry-erase board to exchange messages. Her success is a big influence on Ami and is one of the main reasons why she wants to become a doctor. In Act 34, her mother Saeko got a phone call from the police saying that Ami was out late at night, she decided that Ami's new friends may have been a danger to Ami's education and wanted Ami to transfer to a new school. She had her first fight with her daughter over it. She is genuninely a kind woman who openly regrets not being able to spend more time with her beloved daughter.
Rei's father, is a very high ranked politician. Rei's mother died when Rei was a young child, and her father left her shortly after at the Hikawa shrine with her maternal grandfather, which was Rei's idea. When his wife Risa was dying, he was busy with work, and never came to see her--for which Rei never forgave him. He and Rei have monthly 'lunch dates,' so that he can keep up the appearance of being a loving father to his constituents, but Rei knows the real meaning of the meetings and despises him even more for it. Late in the series, he tries to have Rei move back with him because an election is coming up and he doesn't want to lose face. Rei, however, refuses and spends the night n the Secret Room with Ami, herself having just run away from her mother. Nishizaki is his female secretary and Ishida Shoushi is his personal secretary, both have interacted with Rei. He was never named in past incarinations.