Blanchet was born in Erath, Louisiana, USA, on 8 June 1867, to parents Antoine Reaux and Aurelia LeBlanc.
On 24 January 1887, she married Desire Blanchet (1865–1934). The couple had seven children, including Otto Blanchet (1892–1971), Joseph Otis Blanchet (1894–1965), Odile LeBlanc (1898–1988), and Sidney Blanchet (1903–1984).
In 1961, in her 90s, she moved into Consolata Nursing Home in New Iberia. When asked about the secret of her longevity, she responded that it is “to let a happy smile be more noticeable than snow-white hair and to let an enthusiastic attitude on life overshadow wrinkled hands and a slowed pace in walking.”
Blanchet died at Iberia Parish General Hospital in New Iberia, Louisiana, USA, at 6:10 PM on 9 November 1979, at the age of 112 years, 154 days. She was survived by two of her children, 20 grandchildren, 40 great-grandchildren, 30 great-great-grandchildren, and four great-great-great-grandchildren.