Marie-Louise Febronie Chasse was born in Kamouraska, Quebec, in 1880, to fisherman parents. According to her family, she had some Native American ancestry. At the age of 20, she married Étienne Leclerc, another fisherman in her village. After he, two of her children, and both of her parents died in 1911 and 1912, Meilleur left two of her four surviving children in 1913 and moved to the rural Ontario border. Only once, in 1939, did she return to the Quebec area. She married 1915 Hector Meilleur, a Franco-Ontarian woodcutter, and with him, she had another 6 children.

Marie-Louise lived in a wooden house without electricity and hot water until the 1950s. Some sources said that she was vegetarian, but this is not confirmed. Marie-Louise smoked Tobacco until her 90’s. She lived in Deep River. At 107 years old, she left for a nursing home in East Ferris. At the age of 110, Meilleur was still able to walk without assistance. She attributed her longevity to “Hard work, remembering the good times of her youth, loving her family, having a good sense of humor, and having good faith in God and Mary”.