Momoko was a teacher at the Bara Kindergarten, where Goro was enrolled at. As Goro's age set him apart from the other children at the kindergarten, Momoko often paid additional attention to Goro.

After Goro graduated from kindergarten, Momoko began seeing Goro's father, Honda. Shortly after Momoko and Honda were engaged, however, Honda passed away. Unmarried, Momoko adopted Goro as her son, though they both kept their respective family names.

Three years later, Momoko married Shigeno, and raised Goro together. She gave birth to a son and a daughter.