Dubbed the 'iron lady' by commentators, Rousseff has been trying to soften her public image [AFP]
Dilma Rousseff began her political career as a Marxist guerrilla, but Brazil's former cabinet chief - dubbed the 'iron lady' by some commentators - seems poised to become the first female to lead the world's 8th largest economy.
Rousseff, 62, has promised to continue the popular policies of Luiz Inacio Lula da Silva, her mentor from the left-leaning Workers Party and Brazil's outgoing president.
"After this great man, Brazil will be governed by a woman, a woman who will continue the Brazil of Lula," Rousseff said in June when Lula's ruling Workers Party officially launched her candidacy.
Known for her brusque political style, Rousseff has a reputation for publicly dressing down ministers, although she has recently attempted to soften her image.
"She's an extremely strong woman on one hand, whose posts normally in Brazil were identified with men, not women. Little by little she is working on showing other characteristics to be 'introduced' to different voters," Maria do Socorro Sousa Braga, a political analyst at the University of Sao Paulo, said.
Some changes to her image include replacing stern glasses with contact lenses, undergoing plastic surgery and adopting a more glamorous hairstyle.
Rousseff came to national prominence in 2005, when she was working as Brazil's energy minister.
A financing scandal hit the Workers Party, prompting several leading officials to resign and she became chief of the cabinet.
By 2007, Lula was promoting Rousseff as the "mother" of his government's plan to accelerate economic growth by investing massively in infrastructure projects.
The decision paid off, as Brazil has experienced sustained growth.
Though she does not share Lula's personal charisma, his support seems to have been enough to win over voters, especially poorer ones who have benefited from eight years of anti-poverty programmes instituted by Lula's government.
Rousseff was born in December 1947 in the southwestern state of Minas Gerais to a Bulgarian immigrant father and a Brazilian mother.
After becoming an active militant in an underground group seeking to overturn the military dictatorship that ruled Brazil from 1964 to 1985, she was arrested in January 1970 and sentenced to six years in prison.
After nearly three years behind bars, where she was tortured, she was released, at the end of 1972.
In 1980 she became involved in a leftist populist party, the Democratic Workers Party, but left them in 1986 to join the Workers Party.
Married twice, Rousseff has one daughter, Paula, and became a grandmother in September.
Last year, Rousseff admitted she was undergoing treatment for lymphatic cancer, which generated public sympathy. Her doctors said they believe she is now cured.
If elected, she will be tasked with preparing Brazil for major events, including the World Cup and the Olympics, which will require heavy infrastructure investment.
Abroad, a president Dilma will be seen as likely to continue Lula's diplomatic strategy of being friendly with all nations, including South American neighbours such as Venezuela and Bolivia, both of which take anti-US line.