Jong was born in Nagoya, Japan between a father who has South Korean citizenship and a mother who has Joseon citizenship, and became a South Korean national based on the father's family register at the time of birth. According to, his legal nationality is South Korean. But his mother's nationality is Chōsen-seki, so he can choose the North Korea national football team. His mother sent him to attend a private school in Japan run by Chongryon, a group closely tied to the North Korean government – where he started football at its elementary school club. He later attended Korea University, a private university in Tokyo also funded by Chongryon. Consequently, Jong has said that he and his family identify themselves as North Koreans. Chongryon, North Korea's de facto embassy in Japan, issued a North Korean passport to him. This made him eligible, per FIFA rules, to play for North Korea and resulted in de facto dual nationality. FIFA and AFC regarded him as de facto dual nationality Jong is fluent in Korean and Japanese. He also knows how to speak Portuguese which he learned from his Brazilian teammates at Japan's Kawasaki Frontale. He also speaks German from playing in Germany. He speaks cursory English, due to his trial in Blackburn. Jong publicly emphasized the separation between sportsmanship and politics after the disputes before and during the match between North Korea and Japan on 15 November 2011.
Club career
After joining Kawasaki Frontale in 2006, the striker quickly rose to become one of Kawasaki's best players and one of the best strikers in the J-League. Jong went for a trial with English club Blackburn Rovers in early 2010. After the 2010 World Cup, Jong joined German club VfL Bochum. After one and half seasons in the 2. Bundesliga, Jong transferred to 1. FC Köln in the Bundesliga in January 2012, following an injury to German international Lukas Podolski. However, his time at 1. FC Köln was marred by a lack of playing time. On 3 January 2013, Jong announced that after he would start playing for the first-division South Korean K-League club, Suwon Samsung Bluewings. He had expressed interest in the move for several months before the announcement, and the Bluewings and Ulsan Hyundai FC had both been negotiating with him. Jong joined the South Korean outfit on 10 January 2013 for a reported fee of €300,000 from 1. FC Köln. After deliberation by K League 1 and FIFA authorities, Jong was registered as a South Korean player in the K-League and AFC Champions League competitions. On 6 April, he scored his debut goal for Suwon in a 3–1 home win against Daegu FC. Two weeks later, 20 April, he scored a hat-trick in a 4–1 win at Daejeon Citizen. On 8 July 2015 he was bought by Shimizu S-Pulse as an emergency signing as Shimizu were in the drop zone after total points calculation from both stages of the season. He was inserted into the starting lineup on 25 July, Matchday 4 of the 2nd stage, away to his former club Kawasaki Frontale which ended in a 2–3 defeat.
