Ishii was born in Tomai Village (now Ninohe City), Iwate Prefecture, on 15 September 1904. She married Yoshimitsu Ishii aged 24; the couple had seven children. Her husband worked as a farmer in Takko, Aomori Prefecture, where she later relocated to.
After she was widowed and her children had moved away, Ishii lived independently until 2002, when she moved into a care facility in Takko. Her favourite things to watch on television were professional sumo wrestling, anime, and comedies. She enjoyed conversing with care home staff, relaxing in the bath, and eating snacks and sweet foods between mealtimes.
Ishii’s 112th birthday was celebrated by local dignitaries including Takko’s mayor. Her gifts included a congratulatory letter, a bouquet of flowers, and a hand-made blanket. She claimed the secret to her longevity was, “Eating anything and not being fussy about food.”
Ishii died on 4 March 2017 at the age of 112 years, 170 days. She was survived by her 11 grandchildren, 15 great-grandchildren, and four great-great-grandchildren.