In 1980, he was appointed section leader of his bureau. In 1984, he joined the Ministry of Foreign Affairs, and in 1986 he became First Vice Foreign Minister, a position which he held until 2010.[2]
In the 1990s, he was prominently involved in diplomatic talks with the United States over the issue of his country's nuclear programme. He negotiated the Agreed Framework with Assistant Secretary of State Robert Gallucci and former U.S. President Jimmy Carter in 1994.[3] He was subsequently in charge of supervising North Korea's relations with the United States, which became his area of expertise.[2]Reuters states that Kang "engineered the development of the North's nuclear programme that [...] has been the key source of regional security tensions".[4]
KBS describes him as being "among a handful of well-known North Korean officials", who has "gained global attention", and adds: "Considered too aggressive at times, Kang sometimes caused problems with his pushy demeanor. In the early 1990s, he made several crucial decisions without consulting the party and was sent to a concentration camp for training in revolutionary discipline".[2]