Born the daughter of Mogami Yoshimori, lord of Yamagata Castle in Dewa Province, and younger sister of Mogami Yoshiaki. She married Date Terumune and gave birth to Date Masamune and his younger brother Kojiro. As the relationship between her brother Yoshiaki and her son Masamune grew hostile, she increasingly sided with the Mogami, raising tensions between the two clans. The most widely known legend is the 'Yoshihime poisoning attempt': concerned that those around Masamune were grooming Kojiro—whom Masamune doted on excessively—as the next head of the Date, she is said to have poisoned Masamune's food. Masamune reportedly detected it and expelled the poison, but the truth of whether a mother truly attempted to kill her own son has never been established. Shortly afterward Kojiro was put to death by Masamune. The abduction and killing of her husband Terumune by Nihonmatsu Yoshitsugu in 1584 is also said to have left deep wounds on Yoshihime. In her later years she took refuge with her brother Yoshiaki, and after the Mogami Disturbance she reportedly moved to Sendai to spend her final years.

A woman of strong personality and will. Her pride in the Mogami bloodline was fierce, and even after marrying into the Date she never fully relinquished her ties to home. Her relationship with Masamune was complex—a lifelong mix of maternal love and political rivalry.

The poisoning legend, though unverified, is widely known as a symbol of the complex mother-child dynamics of the Sengoku era. She is remembered as a bridge between the Mogami and Date clans, deeply intertwined with the history of both.