The chief character. A student of Tobita Junior High School in "the Sama hill," in the suburbs of Tokyo. Her powers are awakened by an unexpected coincidence and she uses the power for acts of kindness afterward. She is bright, but careless and rather meddlesome. Mami isn't very good at studying or housework, especially cooking, which becomes a recurring joke throughout the series.

Her father is an artist, and Mami usually poses as nude model for his painting. She was going to reveal her supernatural power to her father, but her friend Kazuo told her that her French ancestors were hunted as witches, and refrains from telling him. She is sometimes called "Mami duke" by her father.

Mami has red hair. She wears a white shirt with a sailor neckerchief, a light blue scarf, blue skirt, white socks and black shoes. When Mami prepared to fly in the sky every night, she wears a white shirt with short sleeves, blue dress, white socks and black shoes.

Mami's main power is telekinesis. She also possesses a levitation ability (she can float not only herself but several objects at the same time), telepathy, and teleportation, although, she often collides with objects and other people. Takahata created a teleportation gun, so that Mami can control her teleportation.