Grant represented Australia at the Beijing 2008 Olympics where he won a bronze medal in the 4 x 200m freestyle relay alongside teammates Pat Murphy, Grant Hackett and Nick Frost.

Prior to this Grant and his team won a silver medal representing Australia at the 2007 World Aquatics Championship in Melbourne in the 4 x 200m freestyle relay. Later that same year at Australian Short Course Championships Grant and his team broke the world record for the 4 x 200m freestyle relay with a time of 6:52.66.