Leroy was born in Nantes, Loire-Atlantique, on 3 July 1913. She married in 1937 and had at least one son. During World War II, she lived and worked in Cugand, Vendée department, as a notary while her husband was in the army.
In 1946, Leroy became a councillor for Cugand, and worked her way up to become the first female mayor of the commune in 1969. She held the position for 14 years until her retirement in 1983.
In 2021, aged 107, Leroy was awarded the Légion d’Honneur, the highest order of merit in France. At the age of 110, she resides in her hometown of Nantes.