Cape Town - Barack Obama is half African through his late father, who was Kenyan.
The US president will embark on Wednesday on his most important trip to the continent since he took office in January 2009. The journey will take him through Senegal, South Africa and Tanzania until July 3.
Obama's only other trip to sub-Saharan Africa was to Ghana shortly after he took office, and even White House officials conceded this week's visit is long overdue.
"This is a region that, frankly, has been underrepresented in our travel," Ben Rhodes, Obama's deputy national security advisor, told reporters in a pre-trip briefing.
A driving interest underlying Obama's journey is Africa's economic boom and the investment competition coming from other parts of the world, including China. Obama will travel with a large economic and trade team.
Deeper partnerships in Africa will advance American interests, "particularly because Africa's economic growth is going to support increasing demand for US exports," said Grant Harris, senior director for African affairs on the national security staff.
African leaders are jubilant about the prospect of the visit by the first black US leader.
But the skirmishes among ruling elites over invitations to Obama events brought scorn from one South African critic, Isaac Mpho Mogotsi of the Cedia political institute in Johannesburg. He called the scrapping "embarrassing African flummery" and "undignified".
"You will be forgiven for thinking that the black African elites are engaged in a frenzied dress-rehearsal for the second coming of Jesus Christ," he wrote.
Little remains of the Obama mania that prevailed during his first election in 2008. Hopes that Obama would spend more tax dollars in African aide have been dashed. There are even protests against him expected in Johannesburg and Cape Town.
Nonetheless, the South African weekly Mail & Guardian declared the Obama visit to be "the most important event of the decade".
"Frankly, we see Africa as one of the most important emerging regions in the world, and a place for the US to significantly increase our engagement in the years to come," Rhodes said in Washington.
Economic windfall
Africa's annual growth spurts of more than 5% in recent years have whetted the appetites of US investors. Although bitter poverty prevails across much of the sub-Saharan region, exports of raw materials have boomed.
Corruption is widespread, and development lags in the poorer countries. Nonetheless, US companies want to be on the ground for the economic windfall.
Obama's journey is all the more important because China has raced ahead with high-powered investments, replacing the United States and European Union as Africa's most important trade partner.
The White House has "heard a high demand signal from the US private sector" for a more active trade and investment role in Africa, Rhodes said.
Other issues on the agenda with leaders will likely include democracy, corruption and threats from Islamist militants.
Obama plans to deliver a major speech on Sunday in Cape Town on US-Africa policy. There's little doubt that a major focus of the speech will be the need for initiative from within Africa for economic development.
Gone are the times when African leaders could excuse their problems of governance and self aggrandizement as the result of colonialism.
Rhodes rejected the notion that the only way for a foreign leader to make an impact in Africa is to announce a high-dollar assistance programme: "The point is, Africa doesn't need handouts. Africa needs trade. Africa needs economic growth."