On 28 July 2012, Jin won the gold medal in the men's 10 m air pistol at the 2012 Summer Olympics. On 5 August, he won the gold medal in the 50m, becoming the first man to successfully defend the 50-metre pistol Olympic title. By doing so, Jin also became the first man to win the 10 metre air pistol and 50 metre pistol gold medals at the same Olympics, and one of the five shooters to win two individual gold medals at one Olympics, being the first man to have done so since Otto Olsen of Norway at the 1920 Summer Olympics. He is one of three shooters to have won three Olympic individual gold medals, along with Ralf Schumann of Germany and Kim Rhode of the United States. He became the first Korean athlete to win three individual Olympic gold medals, to win four (and five) individual Olympic medals, to defend an individual title in the Summer Olympics (while Sim Kwon-Ho won Olympic gold medals for Greco-Roman wrestling in 1996 and 2000, he won two different weight divisions), to win two individual gold medals at one Summer Olympic Games and to win an individual medal for one event at three consecutive Olympic Games (Kim Soo-Nyung won individual gold, silver and bronze medals respectively for archery in the 1988, 1992 and 2000 but these Olympics were non-consecutive).
On 9 September 2014, Jin won the 50 metre pistol gold medal at the 2014 World Shooting Championships after shooting 583 points out of possible 600 in the qualification, thereby breaking the 34-year old World Record of 581 points set by Soviet Aleksandr Melentyev at the 1980 Summer Olympics. In doing so, Jin also set several milestones not seen in 50-metre pistol since the current quadrennial intervals between the world championships were established after the 1954 World Championships; World championships were previously held annually until 1931 (with exceptions) then biennially until 1954. He became the first shooter since 1952 (and fourth overall) to have won three world-level championships (Olympics and world championships) and the first since the 1956 Summer Olympics (fourth overall) to simultaneously hold the Olympic and World titles in the discipline. He also became the second 50 metre pistol shooter (after Ragnar Skanåker in 1993) to have won the Olympics, the world championships and the World Cup Final. Two days later he also won the 10 metre air pistol gold medal at the same world championships.