Shinobu Hayashi was born in Ueki (present-day Kita-ku ward of Kumamoto City), Kumamoto Prefecture, Japan on 15 March 1909. She was the second youngest of six or eight siblings. Her brothers all died young, but one older sister lived to be 102 years old, and one younger sister lived to be 104 years old.

In 1932, she married Hiroki Hayashi. The couple had three children (two sons and a daughter). Around 1943, when she was 34, her husband died, and she was left to raise the children on her own. Until she turned 60, she walked 3 kilometers (1.8 miles) each way from her home to work at the Agricultural Experiment Station in Koshi City, Kumamoto Prefecture every day.

When she lived at home, she loved cleaning and tidying up and never sat still.

At the age of 104, she moved into the Kikkoen Nursing Home (Japanese: 菊香園) in Kōshi. She was able to walk on her own until she was 108. At the nursing home, she enjoyed watching TV, especially cooking shows and sumo matches. On her 110th birthday in March 2019, Hayashi was honored by the mayor of Kōshi, Yoshiyuki Araki.

In October 2022, Hayashi was congratulated on her longevity by the Governor of Kumamoto Prefecture. At that time, Kumamon, a local character from Kumamoto Prefecture, also appeared, and she pointed at Kumamon and asked her granddaughter, “What is that?”

At 113, she had retained her cognitive abilities and she bowed deeply to the governor.

Shinobu Hayashi passed away in Kōshi, Kumamoto Prefecture, Japan, on 25 January 2023, at the age of 113 years, 316 days.