Gloria Castellanos de Álvarez was born in Puerto Plata, Puerto Plata Province, Dominican Republic, on 16 September 1905. She married the poet Francisco Álvarez Almánzar, with whom she had three children: journalist Francisco (1932–2023), and lawyers Juan and Rafael Álvarez Castellanos.
A lifelong educator, she taught in both public and private schools throughout the country. She also served as the personal assistant to renowned educator Ercilia Pepín. Beyond raising her own children to become accomplished professionals, she took on a similar role in the lives of several of her grandchildren, guiding and supporting their education and development.
Gloria Castellanos de Álvarez passed away in Santo Domingo, on 21 September 2016, five days after her 111th birthday.
Her age was verified by Santiago García Medina and Stefan Maglov, and validated by the Latin American Supercentenarians (LAS) on 26 May 2021.