Morgan Tsvangirai vowed to rebuild Zimbabwe's shattered economy and end political violence, as he was sworn in as prime minister in a unity government with long-time rival President Robert Mugabe.
Mr Tsvangirai spoke to more than 10,000 cheering supporters on Wednesday, setting out ambitious priorities to turn around a country mired in economic and humanitarian crisis.
"Political violence must end today. We can no longer afford brother against brother, because one happened to have a different political opinion," Mr Tsvangirai said to cheers.
"The transitional government will make food available and affordable," he said. "Our hospitals must be places of healing... On Monday, all schools must reopen. This Monday."
He also vowed to take some immediate steps to fix the economy, like paying civil servants in foreign currency, but warned that curbing world-record inflation and 94% unemployment would take time.
Both Mr Tsvangirai and Mr Mugabe, speaking at the presidential mansion after the swearing-in, acknowledged the mistrust that marred their negotiations, but vowed to make the unity government work.
Year of turmoil
Mr Tsvangirai's swearing-in caps nearly a year of turmoil that began last March, when he won a first-round presidential vote that was greeted with nationwide political violence, mostly against his supporters.
Hoping to end the unrest that left at least 180 dead, Mr Tsvangirai pulled out of the run-off and left President Mugabe to claim a one-sided victory denounced as a sham overseas.
South Africa brokered the unity deal, which was signed on 15 September but stalled amid protracted talks on how to distribute cabinet posts and share control of the security forces.
The parties finally agreed to name co-ministers to home affairs, which oversees the police, and to create a new National Security Council that will give all parties control of the security forces.
The challenges facing Zimbabwe would daunt even the most experienced of administrators.
More than half the population needs emergency food aid. Unemployment is at 94%.
Only 20% of children go to school because teachers have not been paid and exams not graded.
Public hospitals are closed, with doctors and nurses unpaid, exacerbating a health crisis in a nation where 1.3 million people have HIV and cholera has hit nearly 70,000 people since August, killing about 3,400.