At the 2012 U.S. Olympic Trials, the qualifying meet for the Olympics, McLean made the Olympic team for the first time by finishing fifth in the 200-meter freestyle with a time of 1:46.78, which qualified him to swim in the 4×200-meter freestyle as a member of the U.S. relay team. At the 2012 Summer Olympics in London, he earned a gold medal by swimming for the winning U.S. team in the preliminaries of the 4×200-meter freestyle relay.