Shigeyo Nakachi was born as Shigeyo Hiraishi in Saga, Japan on 1 February 1905, as the second of seven siblings. Her mother was Kayo Hiraishi. In 1911, she entered elementary school. In 1913, she received an award for excellence. In 1916, she graduated from elementary school.
In 1923, she became a teacher. In 1929, at the age of 24, she married Goro Nakachi. The couple had one son: Kenzo. After the end of World War II, she began teaching at an elementary school dedicated to those returning from Manchuria.
She became a kindergarten teacher when she was age 46. Her husband died in 1961. She retired as a kindergarten teacher in 1967 at the age of 62.
Nakachi suffered from breast cancer at the age of 80 and underwent surgery to remove one of her breasts. After retiring, Nakachi enjoyed traveling around Japan with her ex-students and her hobby tea ceremony friends until the age of 92.
She fell on the bus at the age of 92 and broke her femur. She then broke her opposite femur at the age of 93 and around her buttocks at the age of 101, but until the age of 106, she lived with her family at home. At the age of 108, she could walk unassisted. Nakachi enjoyed hand-dancing. She was almost completely deaf. In February 2014, December 2018, and April 2019, she recovered from a bout of aspiration pneumonia that left her bedridden and required a breathing tube for several days.
Nakachi died in Saga City, Saga Prefecture, Japan, on 11 January 2021 at the age of 115 years, 345 days.