Ramaphosa was elected as the new leader of South Africa’s ruling ANC party on Monday.
He took the oath of office on Saturday in front of some 30,000 people at a stadium in the capital, Pretoria, with several regional leaders from the Democratic Republic of Congo, Zimbabwe, Mozambique and elsewhere in attendance.
“A new era has dawned in our country. A brighter day is rising upon South Africa,” said Ramaphosa, promising that the nation was beginning “a new era of hope and renewal”.
“The challenges our country face are huge and real. But they are not insurmountable. They can be solved. And I stand here today saying they are going to be solved,” the 66-year-old said.
The inauguration followed his ruling African National Congress (ANC) party’s 57.5 percent victory in this month’s election. It was the party’s weakest election showing since the ANC took power at the end of apartheid in 1994.
Ramaphosa first took office last year after former President Jacob Zuma was pressured to resign amid corruption scandals that badly damaged public faith in the ANC.
A former protege of South Africa’s first black President Nelson Mandela, Ramaphosa is seen by many as having the potential to clean up both the government and the ruling party’s reputation.
Without him the ANC likely would have received just 40 percent of the vote, one party leader, Fikile Mbalula, has said.
Al Jazeera’s Fahmida Miller, reporting from Pretoria, said the president called for equality and preservation of the country’s resources.
“He said this will be a different era, an era that he will tackle the challenges of poverty, inequality, unemployment that affects almost half of the young people in the country,” she said.
“He also made reference to the last few years as nine wasted years where government institutions were looted and that corruption caused many lost opportunities.”
South Africa has the most advanced infrastructure in the continent, but its commodities-dependent economy has been in a slump for a decade.
It grew by an anaemic 0.8 percent last year and slipped into a brief recession during the third quarter of 2018. It is projected by the World Bank to expand by 1.3 percent this year.
Unemployment is running at 27.6 percent, but among the 20.3 million South Africans aged between 15-34 reaches 55.2 percent.
Ramaphosa also vowed to continue the fight against mismanagement and corruption that has hurt the country’s economy, the most developed in sub-Saharan Africa.
There was no sign at Saturday’s ceremony of Zuma, who has insisted he did nothing wrong and that allegations are politically motivated.
Alleged corruption under Zuma – known as “state capture” – saw millions of dollars siphoned off through government and state agencies awarding fraudulent contracts to favoured companies in return for bribes.
Zuma himself is facing trial for alleged corruption relating to a multibillion-dollar arms deal in the 1990s.
Ramaphosa in February announced he would set up a special tribunal of seven senior judges for “fast-tracking” the recovery of proceeds from corruption cases.