Gerardo Fernández began competing in weightlifting from a young age, becoming a champion at the 1969 National Schools Games in Cuba before becoming the national junior champion from 1971 to 1973. Fernández was soon selected to represent the national weightlifting team in the super-heavyweight class. At the 1975 Pan American Games he won gold in both the snatch and total, along with silver in the clean & jerk. One year later he finished sixth at the Montréal Olympics, before placing fifth at the 1977 World Championships in Stuttgart. Fernández returned to the Olympics for the 1980 Moskva Games, but did not succeed in providing a valid lift. After retiring he worked as a youth coach in both Cuba and Venezuela.