Kim has been suffering from various ailments including diabetes and heart disease. He is understood to have suffered a stroke in 2008 but appeared fit and healthy during his various trips undertaken to China and Russia.
Kim Jong Il inherited power after his father, revered North Korean founder Kim Il Sung, died in 1994. The departed leader had a great affinity for the good things in life like cigars, cognac and gourmet cuisine.
Kim was 33 when he was anointed to the top job and was understood to have nuclear ambitions for his country. He is credited to have introduced the country's nuclear arms arsenal, which culminated in North Korea's first nuclear test explosion, an underground blast conducted in Oct 2006.
Kim aware of his failing health had named his third son, Kim Jong Un as his successor giving his various high ranks.