Emmerson Mnangagwa has been sworn in as Zimbabwe’s president in a ceremony at a packed stadium in the country’s capital, Harare, BBC reports.
It follows the dramatic departure of Robert Mugabe after 37 years of authoritarian rule.
The former vice-president’s dismissal earlier this month led the ruling Zanu-PF party and the army to intervene and force Mr Mugabe to quit.
Mr Mnangagwa, who had fled the country, returned from exile on Wednesday.
The opposition is urging Mr Mnangagwa, who has been part of the ruling elite, to end the “culture of corruption”.
Although Mr Mnangagwa has unseated Zimbabwe’s long-time ruler, he is still associated by many with some of the worst atrocities committed under the ruling Zanu-PF party since the country gained independence in 1980.
He was the country’s spymaster during the 1980s civil conflict, in which thousands of civilians were killed. But he has denied any role in the massacres, blaming the army.
After being sacked as part of a power struggle over who would succeed Mr Mugabe as president, Mr Mnangagwa fled to South Africa two weeks ago – only to return home on Wednesday to a hero’s welcome.