Her paternal grandfather, Katamori Matsudaira, was the last daimyō of the Aizu Domain and head of the Aizu-Matsudaira cadet branch of the Tokugawa.

Her mother's elder sister, Itsuko (1882–1976), married Prince Morimasa Nashimoto, an uncle of Empress Kōjun.

Upon her return to Japan, Setsuko was chosen by Empress Teimei to marry her second son, Yasuhito, Prince Chichibu, despite the fact she was a commoner.

[6][7][8] The bride and groom were eighth cousins, thrice removed, as both were descended from Nabeshima Katsushige, the first lord of Saga.

[17][18] Princess Chichibu's autobiography, which was published posthumously as The Silver Drum: A Japanese Imperial Memoir, was translated into English by Dorothy Britton.