Juan Gabriel Hernández Matamoros was born in Naranjo, Alajuela Province, Costa Rica on 19 October 1913. He was one of 11 siblings born to parents Simón Hernández Guzmán (1876-1927) and Ana Fermina Matamoros Cordero (1879-1960). His parents were the neighbors of Salustio Camacho and Zeneida Quiros, who were the parents of former First Lady of Costa Rica and fellow supercentenarian, Marita Camacho Quirós. He attended school until the fourth grade, before leaving to work on the family farm, where he helped grow coffee, sugarcane, bananas, and yucca. After earning his pay, he would enjoy going to the movie theater in Naranjo, which charged six reales for admission. As some of his uncles were carpenters, he learned the trade from them. He first learned how to make carts for oxen, but later became skilled at many forms of carpentry and construction, leading to a lifelong career that would last for over 60 years, ending with his retirement at the age of 80.

On 22 August 1936, he married Claudia Rodriguez Alvarado (1914-2008), and the couple would go on to have seven children together; they were married for 72 years before Claudia’s death in 2008 at the age of 93.

At the time of his 107th birthday in 2020, he was still active in carpentry, spending a few hours a day in his workshop. Aside from poor hearing and circulation issues forcing him to walk with the aid of a cane, he was reported to be in perfect health, and still exercised on a daily basis. He attributed his longevity to eating well, sleeping at least eight hours a night, avoiding tobacco and liquor, and working hard.

Hernández Matamoros died in Heredia, Heredia Province, Costa Rica, on 20 January 2024, at the age of 110 years, 93 days.