"We can no longer afford brother against brother, because one happened to have a different political opinion.
"The transitional government will make food available and affordable ... no Zimbabwean will ever go hungry again," he said.
"Our hospitals must be places of healing ... all schools must reopen this Monday."
'End of suffering?'
Tsvangirai, speaking in front of 10,000 supporters after his swearing-in ceremony in Harare, the capital, cautioned that improvements would take time under the newly formed unity government between the MDC and Mugabe's Zanu-PF.
"It would take time to implement unity of purpose, to rebuild our country," he said.
Zimbabwe is suffering more than 90 per cent unemployment and runaway inflation, and Tsvangirai said that a primary move would be to pay civil servants in foreign currency.
Haru Mutasa, Al Jazeera's correspondent in Harare, said the key to Zimbabwe's future was whether Tsvangirai and Mugabe could put their enmity aside.
"People are going to wait to see what is going to happen," she said.
"Morgan Tsvangirai has made a lot of compromises, so has President Mugabe.
"The question is, is this all for show, or is President Mugabe actually going to make an effort to hold out a hand to the prime minister and try to end Zimbabwe's suffering?"
Mutasa said there were doubts over whether the unity government - which has taken more than four months to come together after the signing of a power-sharing deal - could last for any significant period of time.
"From what Zimbabweans have seen in the past, it is going to be a long, difficult road," she said.
Tsvangirai inauguration speech highlights
- "The first priority is to stabilise the economy."
- "Political violence must end today."
- "The culture of impunity and of violation of human rights must end, and it must end today."
- "I offer my hand of friendship and co-operation, warm co-operation and solidarity, in the service of our great country Zimbabwe."
- "If yesterday we were adversaries ... today we stand in unity. It is a victory for Zimbabwe."
"[That] the MDC has been given some key ministries - finance and co-sharing home affairs and health - could mean that they will be able to turn around the economy and help the humanitarian crisis."
Cholera has also broken out in the southern African nation, killing about 3,500 people since August.
Some of the MDC's supporters are still held in prison and the movement has said they have to be released.
Geoffery Hawker, an Africa expert at Macquarie University in Australia, told Al Jazeera that power sharing is a gamble for Tsvangirai, but that he had little alternative.
"He's been outside the tent for such a long time ... his supporters are growing very dispirited," Hawker said.
"I don't have any doubt at all that Mugabe is going to bide his time and see if he can cut him off, render him powerless ... so that Mugabe remains in control.
"I do think in the next two, three weeks, we will see if the power sharing works on the ground. And that is the real test."
Political violence broke out in Zimbabwe after disputed elections in March 2008.
Mugabe then won an unopposed presidential run-off in June, after which a South African-brokered power-sharing deal was signed.
But the sides could not agree on how to divide up cabinet positions, leading to a political impasse since September.
The dispute was ended by an agreement which saw the two parties name co-ministers to the home affairs ministry, which oversees the police force, and the creation of a new National Security Council.