Ernesta García Hernández was born in Aguas Buenas, Puerto Rico, on 7 November 1910. She was the third of eleven children born to parents Juan García Pagán (1880–1965) and Eleuteria Hernández (1886–1985).

At some point, she married Lazarro Agosto in Puerto Rico. The couple had five children. Her husband passed away around 1947, when Ernesta was 37 years old. Following his passing, she began washing clothes for other people in an effort to provide for her children.

García Hernández came to New York in 1964 for the birth of her first grandchild, and decided to stay. She began working at a scissor factory and at a company where she would produce women’s undergarments. In 1967, she moved to Bridgeport, Connecticut, where she worked at various Spanish restaurants.

As of her 107th birthday, she had 11 grandchildren, 18 great-grandchildren and nine great-great-grandchildren.

García Hernández passed away in Bridgeport, Connecticut, USA, at the age of 110 years, 254 days.