A former Marxist guerrilla who was tortured and imprisoned during Brazil's long dictatorship was elected as president of Latin America's biggest nation, a country in the midst of an economic and political rise.
A statement from the Supreme Electoral Court, which oversees elections, said governing party candidate Dilma Rousseff won the election. When she takes office on January 1, she will be Brazil's first female leader.
With 99 per cent of the ballots counted, Rousseff had 55.6 per cent compared to 44.4 per cent for her centrist rival, Jose Serra, the electoral court said.
"I'm very happy. I want to thank all Brazilians for this moment and I promise to honour the trust they have shown me," Rousseff told reporters who swarmed a car carrying her in Brasilia, her first public words as president-elect.
Rousseff, the hand-chosen candidate of wildly popular President Luiz Inacio Lula da Silva, won by cementing her image to Silva's, whose policies she promised to continue.
She will lead a nation on the rise, a country that will host the 2014 World Cup and that is expected to be the globe's fifth-largest economy by the time it hosts the 2016 Summer Olympics. It has also recently discovered huge oil reserves off its coast.
Rousseff was already speaking like a president-elect before the result was announced.
"Starting tomorrow we begin a new stage of democracy," Rousseff, 62, said in the southern city of Porto Alegre, where she cast her vote.
"I will rule for everyone, speak with all Brazilians, without exception".
Silva used his 80 per cent approval ratings to campaign incessantly for Rousseff, his former chief of staff and political protege. She never has held elected office and lacks the charisma that transformed Silva from a one-time shoeshine boy into one of the globe's most popular leaders.
Silva was barred by the constitution from running for a third consecutive four-year term. He has batted down chatter in Brazil's press that he is setting himself up for a new run at the presidency in 2014, which would be legal.
Despite Rousseff's win, many voters don't want 'Lula', as he is popularly known, to go away.
"If Lula ran for president 10 times, I would vote for him 10 times," said Marisa Santos, a 43-year-old selling her homemade jewelry on a Sao Paulo street. "I'm voting for Dilma, of course, but the truth is it will still be Lula who will lead us".
Within 20 minutes of Rousseff's victory being announced, her supporters began streaming onto a main avenue in Sao Paulo, where eight years ago a huge gathering celebrated Silva's win, the first time the Workers Party took the presidency. Police blocked off the road and workers were already constructing a stage for a party expected to last the entire night.