Justina Maria dos Santos was born in the district of Santa Emília in the city of Venâncio Aires, Rio Grande do Sul, Brazil, on 12 May 1913. Her grandmother, Emília Ferreira, allegedly died at the age of 116.

At the age of 19, she married Osvaldino José dos Santos, and the couple had two children: Amélia Maria and Donildo José. In May 2021, she lived in the city of Mato Leitão with her daughter Amélia Maria Freder, granddaughter Dioni and great-granddaughter Nieli. At the time, she had 5 grandchildren, 2 great-grandchildren and 3 great-great-grandchildren.

Justina Maria dos Santos passed away in Mato Leitão, Rio Grande do Sul, Brazil, on 26 January 2022, at the age of 108 years, 259 days.