Veteran peace campaigner Archbishop Desmond Tutu has been awarded $1m (£620,000) by the Mo Ibrahim Foundation for "speaking truth to power".
The London-based Foundation called the cleric "one of Africa's great voices for justice, freedom, democracy and responsible, responsive government".
He won the Nobel Peace Prize - and 10m Swedish Krona (£935,000) - in 1984 for his campaign against apartheid.
Archbishop Tutu responded by thanking his wife, Leah, for her guidance.
"I have been very fortunate throughout my life to be surrounded by people of the highest caliber, beginning with my extraordinary wife," said the archbishop in a statement.
"It is these generous people who have guided, prodded, assisted, cajoled - and ultimately allowed me to take the credit."
The statement said the retired archbishop of Capetown was celebrating his and his wife's birthdays with family and staff - he turns 81 on Sunday, while Mrs Tutu's birthday is a week later.
The South African cleric remains outspoken on international affairs, and has been a fierce critic of Israel's treatment of the Palestinians as well as China's treatment of Tibetans.
In August, he pulled out of a leadership summit in Johannesburg because he refused to share a platform with former UK Prime Minister Tony Blair.
Archbishop Tutu said Mr Blair and former US President George W Bush should be tried at the International Criminal Court in The Hague for lying about Iraq's weapons of mass destruction in order to justify invading the country.
Mr Blair issued a strongly worded defence of his decisions, rejecting the archbishop's allegations as "completely wrong as every single independent analysis of the evidence has shown".
The Mo Ibrahim Foundation also offers an annual $5m prize to a former African head of state for good governance.
The most recent recipient of that award was Cape Verde's former President Pedro Verona Rodrigues Pires in 2011.
Winners must have been democratically elected and agreed to leave office.
In some years the prize has not been awarded because no-one has been deemed a worthy enough winner. The winner of the 2012 prize, if it is awarded, would be announced later this month.
Mo Ibrahim was born in 1946 and is a British-Sudanese mobile communications entrepreneur and philanthropist who made billions from investing in Africa.
He argues that his foundation's $5m prize - the world's most valuable individual prize - is needed because many leaders of sub-Saharan African countries come from poor backgrounds and are tempted to hang on to power for fear that poverty is what awaits them when they give up the levers of power.
The inaugural prize was awarded in 2007 to Joaquim Chissano, Mozambique's former president, who has since acted as a mediator in several African disputes.
After announcing the award for Archbishop Tutu, Mr Ibrahim launched a scathing attack on South Africa's governing African National Congress.
He told the BBC that the party which led the fight to end white minority rule should "go back to its roots" and needed some "soul-searching".
He also said he was "less enthusiastic" about investing in South Africa than he was five or 10 years ago - but said he was still sure the country had a great future.