Fernandez lived in Santa Clara, Cuba, and made three unsuccessful attempts at defecting before he successfully defected in 2008. He enrolled at Braulio Alonso High School in Tampa, Florida, and was selected by the Marlins in the first round of the 2011 MLB Draft. Fernández made his MLB debut with the Marlins on April 7, 2013. He was named to the 2013 MLB All-Star Game and won the National League (NL) Rookie of the Month Award in July and August. After the season, he won the NL Rookie of the Year Award, and finished third in Cy Young Award balloting.