He began riding professionally in 2003 and achieved his first win on November 29, 2003, at Louisiana's
Delta Downs. As of May 2024, he has over 2,500 victories. On August 18, 2012, he won the 1,000th race of his career at
Ellis Park Race Course and on November 3, 2012, his 27th birthday, he won the
Breeders' Cup Classic aboard
Fort Larned at
Santa Anita Park. In 2024, Hernandez became the ninth jockey in history and the first since
Calvin Borel in 2009 to win both the
Kentucky Oaks and the
Kentucky Derby in the same year. He won the Oaks aboard
Thorpedo Anna then won the Derby the following day on
Mystik Dan. Both horses were trained by
Ken McPeek. In an
interview, Hernandez Jr. told
The Blood-Horse "as a young kid, I'd always ride my bicycle around and tell my mom and dad that I'm going to win the Kentucky Derby". ==Year-end charts==