Hernández was born in Jávea, Spain. His career started in karting in 1998, lasting until 2001 when he moved up to Portuguese Formula BMW. Later in the year he also raced in Spanish Formula SuperToyota, as well as still driving in some karting events, although this stopped at the start of 2002. In 2002 he debuted in Spanish Formula Three, driving for the Azteca team, where he would stay for 2003. In 2003 he also drove for Azteca in British Formula Three, driving some races. He also drove part of the World Series Light season.
He remained in Spanish F3 for 2004, only moving to the Campos team. He also got a taste of World Series by Nissan, driving part of the season for the Saulnier team. In 2005 he drove in the GP2 Series, partnered with Juan Cruz Álvarez, although Campos struggled throughout the season. He moved to Durango for 2006, partnering Lucas Di Grassi, but results were even more sparse.
In 2007 Hernández raced for Proteam Motorsport in a BMW in the WTCC. Also, during the GP2 season finale at Valencia, he drove for the Trident Racing team, replacing Ricardo Risatti who had himself replaced the injured Pastor Maldonado for three race meetings. He continues to race for Proteam in 2008.
Racing record
Complete GP2 Series results
(key) (Races in bold indicate pole position) (Races in italics indicate fastest lap)