At the 2012 London Olympics, Tallent finished 7th in the 20 km walk. A week later he won the gold medal in the 50 km walk in a personal best time and Olympic Record of 3:36:53. Tallent was initially awarded the silver medal, but on 24 March 2016 the Court of Arbitration for Sport disqualified all results, in the period from 20 August 2009 to 15 October 2012, of doper Sergey Kirdyapkin, who had been the first walker across the line. Tallent received his gold medal for the 2012 Olympics on 17 June 2016 in a special ceremony.