Erina's secretary and close friend, Hisako specializes in medicinal-based dishes. She thinks of Erina as the best, that only she could be Erina's number two and nobody could ever get past her to Erina's level.
She advanced to the main tournament of the Autumn Election where she was defeated by Hayama, who told her that someone who only aims to be second could never beat him. This hurt Hisako's pride and caused her to feel unworthy of being near Erina. While partnered with Sōma for their stagiaire, Hisako reveals her insecurities but Sōma convinces her otherwise and she cheers-up. They then worked together to improve their assigned restaurant with Hisako acting as the restaurant's auditor and business manager while Sōma handled the kitchen. Hisako has since returned to Erina's side and become friendlier towards Sōma.
Hisako once read an old cooking-magazine that featured Erina's father, Azami, but Hisako's own father warned her against ever asking about Azami. When Azami returns and replaces Senzaemon as the academy's director, Hisako is fired as Erina's secretary and becomes extremely depressed. Hisako, Alice and Ryō convince Erina to leave the Nakiri mansion, taking shelter inside the Polar Star Dormitory where Hisako reveals Erina's history. Hisako leaves Erina in their care, though she would visit every day to bring Erina a change of clothes. Hisako sought Sōma as the last hope of restoring the academy, and entrusted Megumi to take care of Erina, before commencing the 3rd stage of the Promotional Exams – where Hisako was defeated by Saito and expelled.