Joyce Banda was sworn in Saturday as Malawi's new president, calling for reconciliation after the divisive Bingu wa Mutharika died in office.
Thunderous applause and joyous singing erupted after she recited her oath making her the nation's first female leader.
Banda quieted the room and held a moment of silence for a man she hailed as a father to the nation.
But she didn't shy away from the divisions provoked by Mutharika, who had expelled her from the ruling party.
He died after a heart attack on Thursday amid calls for his resignation, following deadly anti-government protests last year that accused him of wrecking the economy and trampling on democracy.
"I want all of us to move into the future with hope and with that spirit of one-ness and unity," she said.
"I just sincerely hope that there is no room for revenge. I just sincerely hope that we shall stand united."
Banda's accession to the presidency ends two days of political intrigue, as Mutharika's inner circle sought in vain to block her rise to power.
Since her expulsion from Mutharika's Democratic Progressive Party, she has formed her own People's Party -- a move that his allies argued should disqualify her from succeeding him.
Amid pressure from Western and African powers for a peaceful and constitutional transition, Banda appeared Saturday flanked by the army and police chiefs to call a special cabinet meeting and assert her authority.
"I would like you to know that we felt the Holy Spirit in that room, and I would like you all to know that it was a good meeting" with cabinet, she said.
"For me that was significant, because that is the starting point for healing the wounds of this nation."
"I want to sincerely thank Malawians and all people living in Malawi for the respect of the law shown by the peaceful transition of the presidency," Banda added.
Soldiers guarded the parliament grounds and took over security at state radio and television, as the army publicly backed the transition between civilian leaders.
Mutharika's face still beamed down from billboards on the capital's streets, with his portrait on walls in government offices and private businesses.
Malawi declared 10 days of mourning, and had yet to announce plans for his funeral.
Banda is now the second female African head of state in modern times after Liberia's Ellen Johnson Sirleaf.
She faces the challenge of leading a country whose parliament is dominated by Mutharika's party, at the head of a cabinet that includes ministers vocally opposed to her.
"There was quite a lot of tension and we are glad that it has turned out to be peaceful," said DPP lawmaker Kezzie Msukwa.
"The party has taken it painfully. However, I think everybody now agrees that we have to go the way that we are going."
Mutharika, a former World Bank economist who first came to power in 2004, was re-elected with a sweeping majority in 2009.
But he increasingly came under fire for attempts to rein in the media and to shield the government from public criticism.
His feuds with donors and lenders such as the International Monetary Fund have hamstrung the economy in this aid-dependent nation.
Now Malawi is suffering from shortages of foreign currency that have left it unable to import enough fuel.
When public frustration erupted into nationwide street protests in July, police shot dead 19 people. Last month, a broad coalition of rights groups called on Mutharika to resign.
"We thought he was at the centre of the problems that we were encountering as a country," said Thumbiko Msiska, a non-government organisation worker who attended the swearing in.
"We take this as a divine intervention because there was a call for him to resign. It's actually a divine resignation."