At the 2004 Summer Olympics in Athens, Pinzón finished in thirty-fifth place in the men's 200-meter backstroke. Pinzón competed at the 2008 Summer Olympics in Beijing in the 100 and 200-meter backstroke, the 200 and 400-meter individual medley, and the 200-meter butterfly. His best 2008 Olympic performance was in the 200-meter backstroke, where he placed seventeenth with a time of 1:59.11.
Pinzón won his first gold medal at a Swimming World Cup in Singapore in 2011 in the 200-meter backstroke. Pinzón then won gold medals in Shanghai and Tokyo in the 200-meter backstroke.
Pinzó tested positive for cocaine in November 2012 and was subsequently banned from competing for two years. In 2014, however, after an appeal to the Court of Arbitration for Sport, the suspension was overturned due to several inconsistencies in the testing process.