Benavente Sanhueza was born in Concepción, Biobío Region, Chile, on 25 September 1909. His parents were Manuel José Benavente Benavente Sr. (born 1878) and Celia Sanhueza Saavedra. He had at least 8 siblings.
Several notable ancestors on his paternal side included Diego José Benavente (1790–1867), who was a former Senate President and Minister of Finance of Chile, and José María Benavente (1785–1833), Minister of War and Navy of the Republic of Chile during the Chilean War of Independence against Spain.
At the age of 15, he started working at a courtroom in Coronel, Biobío. In 1934, he moved to San Bernardo, where his father bought a property. Benavente Sanhueza married Sara Salas Iriarte and they had 2 daughters: Pilar and María Elena. He worked in Chile’s Casa de Moneda (a company in charge of printing banknotes, passports, stamps, etc.) for 35 years, where he served as a deputy director. He founded the Portal Freire shopping center in San Bernardo, which was later managed by his grandson, Sebastián Mery.
In 2008, at the age of 99, he obtained the Diego Portales medal, the highest award given by the Confederation of Retail Trade and Tourism of Chile (Spanish: “La Confederación del Comercio Detallista y Turismo de Chile”). He was also recognized as an “illustrious son” of his city.
His sister Mariana (1914–2020) lived to be 105 years, and his sister Cella (born 1921) was alive at the age of 100 in 2021. Three more of his sisters lived to be over 90. His sister Adriana married Julio Canessa Roberts (1925–2015), a Chilean military and political figure.
Benavente Sanhueza died in San Bernardo, Santiago Metropolitan Region, Chile on 21 March 2021 at the age of 111 years, 177 days.
His age was verified by Jeffrey Xu, Stefan Maglov and Fabrizio Villatoro, and validated by the LAS on 26 September 2020.