He later served as the UN special envoy for Syria, leading efforts to find a peaceful solution to the conflict.
Mr Annan’s tenure coincided with the Iraq War and the HIV/AIDS pandemic.
The former UN chief died in the Swiss capital of Bern today after a short illness.
According to the Kofi Annan Foundation Twitter page, Annan was a global statesman and a deeply committed internationalist who fought throughout his life for a fairer and more peaceful world.
During his distinguished career and leadership of the UN, Mr Annan was an ardent champion of peace, sustainable development, human rights and the rule of law.
After stepping down from the UN, he continued to work tirelessly in the cause of peace through his chairmanship of the Kofi Anna Foundation and as chair of The Elders, the group founded by Nelson Mandela, he was an inspiration to young and old.
Mr Annan was a son of Ghana and felt a special responsibility towards Africa.
He was particularly committed to African development and deeply engaged in many initiatives, including his chairmanship of the Africa Progress Panel and his early leadership of the Alliance for a Green Revolution in Africa (AGRA).
Wherever there was suffering or need, Mr Annan reached out and touched many people with his deep compassion and empathy.
He selflessly placed others first, radiating genuine kindness, warmth and brilliance in all he did.
Only three weeks ago, Mr Annan was in Zimbabwe as chairman of The Elders group, for a three day visit where they met political parties and other interested players for the 30th July harmonised polls.