[1] Sumiko was the daughter of Emperor Ninkō and his lady-in-waiting, Kanroji Kiyoko.
She was the elder half-sister of Chikako, Princess Kazu and Emperor Kōmei.
On May 3, 1840, she was engaged with her cousin Prince Kan'in Naruhito; she officially became an imperial princess on October 18, 1842, to make way for her marriage.
Afterwards, Princess Sumiko remained unmarried until her death.
The Katsura-no-miya house was one of the four shinnōke, branches of the Imperial Family of Japan which were eligible to succeed to the Chrysanthemum Throne in the event that the main line should die out.