Hernández spent his entire career with hometown club Cartaginés, after joining their youth team in 1957. He made his debut for the senior team in 1962.[2] He was part of the club's famous Ballet Azul squad in the 1970s and became the Costa Rican Primera División top goalscorer in 1973.[3]
In February 2013, Danny Fonseca equalled Hernández' club record of 360 games.[4]
Hernández was born to José Francisco Hernández Madriz and Dolores Valerín Brenes.[2] He is married to María de los Angeles Artavia Luna and they have two daughters. He worked at the audit department at the Banco Crédito Agrícola de Cartago.[7]