Fukasawa was born in Kajikazawa (now part of Fujikawa), Yamanashi Prefecture, Japan, on 21 March 1911. As a young woman, she worked at a paper mill and was involved in farming work. She had children at some point.

In June 2020, at the age of 109, Fukasawa moved into a nursing home in Komuro. At 110, she was reported to be in good health. She could independently operate her wheelchair, ride the care home elevator, maintain a hearty appetite, use chopsticks without staff assistance, and engage in radio gymnastics every morning. Her hobby was origami, and she frequently gifted paper cranes she crafted to the staff.

Fukasawa passed away at a hospital in Fujikawa, Yamanashi Prefecture, Japan, on 15 September 2023.