Sumiko Mori was born in Japan on 30 January 1912. At some point during her youth, she won first prize in a beauty contest. She also enjoyed painting watercolor landscapes, a skill which she taught herself, until she was no longer able to paint due to old age.
In 2011, at the age of 99, she was reported to be in good health, and it was stated that she had never been seriously ill.
On 2 November 2022, following the death of 111-year-old Toku Isaka, she became the oldest living person in Mie Prefecture.
Her age was verified by Japan’s Ministry of Health, Labour, and Welfare (MHLW), as well as Yu Li and Yumi Yamamoto, and validated by LongeviQuest on 21 November 2023.