Irène Castera was born in Port-au-Prince, Haiti on 7 January 1910.
At some point, she married George Castera, with whom she had seven children, one of whom became the author Georges Castera (1936–2020). Her husband died in 1969.
After many trips during her life, notably to the United States, Germany and France where some of her children live, Castera moved to Strasbourg in 2010, after the earthquake struck Haiti. She lived with her son-in-law Jean, and her daughter May. In 2014, she met Pope Francis with two of her daughters. At the time of her 111th birthday in 2021, she had 10 grandchildren and 11 great-grandchildren, and was reported by France to be the oldest in the French region of Alsace (now in Grand Est).