Miho Kumagai was born in Japan on 20 October 1912.

At some point, she moved into a special nursing home for the elderly. In September 2019, at the age of 106, she was visited by city officials at her nursing home where she was presented with a congratulatory letter on behalf of the mayor in celebration of Respect for the Aged Day. She said to the visiting officials, “You didn’t have to do all this for me.” Even at the age of 106, she was reported to take good care of her health on a daily basis and occasionally used a walking frame for mobility training when her condition permitted it. In September 2023, at the age of 111, she was once again visited by city officials at her nursing home. She received congratulatory gifts and a letter on behalf of the mayor in celebration of Respect for the Aged Day. When asked about the secret to her longevity, she replied, “Because everyone is so good to me.”