Entering Boxing at the 2016 Summer Olympics, 20-year-old Hernandez—a virtual unknown in boxing—weighed in at 108 pounds, entering the Men's light flyweight division. Not expected to win, his unexpected Olympic victories created a stir in the boxing community. His USA Olympic boxing coach was Billy Walsh (though his lifelong boxing coach had been his own father, Lewis Hernandez). Ironically, Walsh had previously coached Brendan Irvine, an Irish boxer who, the year before, had defeated Hernandez in the starting round of a world championship fight in Qatar.