In her Olympic debut at the 2008 Summer Olympics in Beijing, Schmitt won a bronze medal as a member of the 4×200-meter freestyle relay. Four years later, at the 2012 Summer Olympics in London, she won a total of five medals, three of them gold, in the 200-meter freestyle (in which she set a new Olympic record), in the 4×200-meter freestyle relay, and in the 4×100-meter medley relay (in which a new world record was set); and she also won a silver medal in the 400 meter freestyle, and a bronze medal in the 4 × 100 meter freestyle relay.