Kim Jong-il was born in an army camp near Khabarovsk in the Soviet Union, where his father, Kim Il-sung, was an important figure among Korean Communist exiles. Kim was three years old when World War II ended and Kim Il-sung returned to Korea to take charge of the Communist apparatus in Pyongyang, in the Soviet-occupied northern half of Korea. The younger Kim's brother, sister, and mother all died under mysterious circumstances, leaving Kim Jong-il as the sole successor to Kim Il-sung. After graduating in 1964, Kim Jong-il began his ascension through the ranks of the ruling Korean Worker's Party, working first in the party's elite Organization Department before being named a member of the Politburo in 1968. In 1969 he was appointed deputy director of the Propaganda and Agitation Department. The elder Kim had meanwhile remarried and had another son, Kim Pyong-il, sparking an intense rivalry between Kim Jong-il and his younger half-brother. It is unclear when Jong-il was chosen over Pyong-il, or whether Pyong-il was ever seriously considered as successor by his father. Kim Pyong-il was eventually posted to a series of distant embassies to keep the two brothers apart. In 1973 Kim was made Party secretary of organization and propaganda, and in 1974, he was officially designated his father's successor. During the next 15 years he accumulated further positions, among them Minister of Culture head of party operations against the Republic of Korea. By the time of the Sixth Party Congress in October 1980, Kim Jong-il's control of the Party operation was complete. He was given senior posts in the Politburo, the Military Commission and the party Secretariat. When he was made a member of the Seventh Supreme People's Assembly in February 1982, it had become apparent to international observers that he was the heir apparent to succeed his father as the supreme leader of the DPRK. In 1991 Kim was also named supreme commander of the DPRK armed forces. Since the Army is the real foundation of power in the DPRK, this was a vital step. It appears that the veteran Defense Minister, Oh Jin-wu, one of Kim Il-sung's most loyal subordinates, engineered Kim Jong-il's acceptance by the Army as the next leader of the DPRK, despite his complete lack of military service. The only other possible leadership candidate, Prime Minister Kim Il (no relation), was removed from his posts in 1976. In 1992, Kim Il-sung publicly stated that his son was in charge of all DPRK internal affairs. (http://en.wikipedia.org/wiki/Kim_Jong_Il)

He took over from his father, who was also revered as the great and beloved leader by the masses who were too afraid of being tied to a pole and kicked to death, if they didn't display anything other than utter adoration for him.

Through his father. He is actually a very smart guy...knows exactly what he's doing... He's got some internal factions to deal with....his will and the "younger/new" regime vs. the old one that helped his father come to power - too bad they're not dead yet.