Sakaguchi graduated from Shōtō Kindergarten, Seijo Gakuen Primary School, Seijo Gakuen Junior High School and High School, and Horikoshi High School. Sakaguchi's mother is actress Ryoko Sakaguchi, her father was formerly a real estate company executive, her stepfather is the professional golfer Tateo Ozaki. She has a brother that is two years older than her. Her parents divorced on 1994, and she grew up with her mother. Sakaguchi was a fan of