Kim Il-sung was the first leader of North Korea, which he ruled from the country's establishment in 1948 until his death in 1994. He held the posts of Premier from 1948 to 1972 and President from 1972 to 1994. He was also the leader of the Workers' Party of Korea from 1949 to 1994 . Coming to power after the end of Japanese rule in 1945, he authorized the invasion of South Korea in 1950, triggering an intervention in defense of South Korea by the United Nations led by the United States. Following the military stalemate in the Korean War, a ceasefire was signed on 27 July 1953. He was the third longest-serving non-royal head of state/government in the 20th century, in office for more than 45 years.
Under his leadership, North Korea was established as a communist state with a publicly owned and planned economy. It had close political and economic relations with the Soviet Union. By the 1960s, North Korea briefly enjoyed a standard of living higher than the South, which was fraught with political instability and economic crises. The situation reversed in the 1970s, as a newly stable South Korea became an economic powerhouse fueled by Japanese and American investment, military aid, and internal economic development, while North Korea stagnated and then declined in the 1980s. Differences emerged between North Korea and the Soviet Union, chief among them being Kim Il-sung's philosophy of Juche, which focused on Korean nationalism, self-reliance, and socialism. Despite this, the country received funds, subsidies and aid from the USSR until the dissolution of the USSR in 1991. The resulting loss of economic aid adversely affected the North's economy, causing widespread famine in 1994. During this period, North Korea also remained critical of the United States defense force's presence in the region, which it considered imperialism, having seized the American ship USS Pueblo in 1968, which was part of an infiltration and subversion campaign to reunify the peninsula under North Korea's rule. He outlived Joseph Stalin by four decades and Mao Zedong by almost two and remained in power during the terms of office of six South Korean Presidents, ten US Presidents, and the rule of British monarchs George VI and later his daughter Elizabeth II. Known as the Great Leader , he established a personality cult which dominates domestic politics in North Korea.
At the 6th WPK Congress in 1980, his oldest son Kim Jong-il was elected as a Presidium member and chosen as his heir apparent to the supreme leadership. Kim Il-sung's birthday is a public holiday in North Korea called the "Day of the Sun". In 1998, Kim Il-sung was declared "eternal President of the Republic". During his rule, North Korea was molded into a totalitarian state responsible for widespread human rights abuses.