Cielo is the current world record holder in the 100-metre and 50-metre freestyle (long course). His gold medal at the 2008 Summer Olympics, in the 50-metre freestyle competition, is Brazil's only Olympic gold in swimming to date. In 2008, he broke the NCAA record in the freestyle (18.47 seconds) and in the freestyle (40.92 seconds). Cielo became the fastest swimmer in the world in the two distances, and was named NCAA Swimmer of the Year for the second year in a row. Cesar currently lives and trains in Itajaí.