On June 24, 2012, in Eugene, Oregon, Bryshon Nellum ran a personal record 44.80—his first sub-45-second time—in the 400 meters at the U.S. Olympic track trials, placing third in the competition and earning a spot on the 2012 Olympic team. At the 2012 Olympics Nellum reached the semi-finals of the individual 400 meters and won a silver medal as part of the 4×400 meters relay team. He carried the US flag at the closing ceremony after being chosen by the US athletes.