To North Koreans, the 69 year old was simply known as the 'Dear Leader.'
Little is known about the isolated dictator, who was said to favor platform shoes and a hairstyle aimed to make Kim appear taller than his five foot three stature.
Kim was a renowned film buff, with a library of 20,000 Hollywood movies. His own state media reported that he hit 11 holes-in-one the first time he played golf.
The reclusive leader didn't like to be photographed, but he made an exception for Bill Clinton.
The former President convinced Kim Jong Il to pardon two jailed journalists accused of spying.
But Kim ran a brutal regime.
He took command of world's fourth largest army in 1991, and has since pumped the country's strapped cash into the development of nuclear weapons and the long range missiles to carry them.
The country's feeble economy became more even more crippled under his rule. Experts say a famine in the late 1990's killed one million of the country's population of 22 million.
North Koreans continue to suffer from widespread malnutrition and dismal living conditions.
Kim also had a reputation as a master manipulator.
When former US Secretary of State Madeleine Albright met Kim she said the North Korean leader was very well informed and "definitely not delusional".
Nuclear armed and isolated, North Korea will likely fall under the rule of Kim Jong Un.
Though an official announcement has yet to be made.