Mitsuko Agawa was born in Hiroshima Prefecture, Japan, on 7 August 1908. She married Koju (born 1901), the older brother of a Japanese author, Hiroyuki Agawa. Her husband died of a sudden illness in 1968.
Agawa lived in her own house in Hiroshima City until she suffered a fall at the age of 97, after which she moved into a nursing home. After her 104th birthday in 2012, she became wheelchair-bound after she started to decline. Her niece, Sawako Agawa (daughter of Hiroyuki), is a Japanese author and television personality.
Mitsuko Agawa died in Naka-ku, Hiroshima City, Hiroshima Prefecture, Japan, on 24 September 2020 at the age of 112 years, 48 days.
Following the death of Hanako Uehara on 24 June 2020, Agawa became the oldest living person in Hiroshima Prefecture.
Her age was verified by Japan’s MHLW, Ryohei Asano and Yu Li, and validated by LongeviQuest on 20 February 2023.