Quénet was born as Anna Marie Josèphe Guillo in Arzon, Morbihan, Brittany on 6 November 1911 as the youngest of eight children. Her parents, Jean-Marie Guillo and Jeanne-Marie Le Hecho, worked as a bricklayer and a housekeeper respectively. She was married thrice and had two sons, Michel and Jean, with her first husband, sailor Auguste Guepin, whom she married in 1933.

Quénet lived in Paris until she was widowed from her final husband, Pierre-Louis Quénet, in 1965, at which point she returned to Arzon. She lived independently until 2015 when, aged 103, she moved into a nursing home due to worsening eyesight. As a centenarian, she enjoyed knitting and listening to the television.

At the time of her 110th birthday, Quénet had two granddaughters, Brigitte and Claudine, as well as five great-grandchildren, 10 great-great-grandchildren, and two great-great-great-grandchildren, the younger of whom was three years old. She lived in the same nursing home as Marie-Louise Dressay (1911 – 2021), who was four months her senior.

Quénet died in Vannes, Morbihan, Brittany on 2 January 2022 at the age of 110 years, 57 days.