While in a relationship with Fugaku Uchiha's brother, she became pregnant and later gave birth to Kimi, her motherly instincts compelling her to raise the child alone. Her life prior to her relationship with Fugaku's brother, or the reason(s) why her lover didn't marry her or help her raise Kimi are largely unknown. Kimi, however, mentions Mikoto helping out her mother financially from time to time. She is seen accompanying Kimi to the village's gates for her first mission, this being the last time she would see her daughter before the Uchiha Clan Massacre.