Born in Arauca, Hernández was bought by Junior in 2000 at the age of 11, while playing for lowly amateurs Mundialito 90. He played for the youth setup before being assigned to the club's reserve team, Barranquilla, in 2007.[1]
Atlético Junior
In 2008, after contributing with 25 appearances and four goals during the previous campaign, Hernández was called up by first team manager Julio Avelino Comesaña. He made his Categoría Primera A debut on 13 September of that year, in a 1–0 home win against Millonarios.[2] He was handed his first start for the Tiburones eight days later, in a 1–0 home success over Envigado.[3]
Hernández only scored his first professional goal on 21 June 2009, netting the equalizer in a 2–2 away draw against Deportivo Cali.[4] He became a regular starter in the 2010 season, contributing with 22 matches and one goal as his side was crowned champions of the Apertura tournament. He scored five goals in the following year, also lifting the Clausura.
Hernández scored his first professional brace on 31 August 2015, in a 3–1 home win against Deportivo Cali.[6] He netted ten league goals in the campaign, also being a winner of Copa Colombia.
Santos
On 13 October 2016, Santos' president Modesto Roma Júnior confirmed the signing of Hernández prior to the 2017 campaign.[7] The rumoured fee was believed to be US$ 1 million.
Hernández made his Série A debut on 14 May 2017; after coming on for Vitor Bueno, he scored his side's second goal in a 3–2 away loss against Fluminense.[10]
Atlético Nacional
On 19 January 2018, Hernández was announced at Atlético Nacional back in his homeland.[11]