Having gone from poverty to parliament via Big Brother and Brazil's first gay-rights election platform, Jean Wyllys must rank among the most postmodern of politicians. How else to describe a professor who exploded into the national consciousness when he entered a reality TV show in 2005 because, he said, it was the only way he could conduct an ethnographic study of how it worked?

Despite the prejudices of what he described as a "homophobic nation", his wit and openness were a huge hit with the public. The gay academic emerged from the Big Brother house as winner. He triumphed in a more traditional popularity contest five years later when he became the first federal deputy to campaign for the LGBT movement. It is a remarkable record for a 39-year-old who grew up on the periphery of a city in Bahia, a northeast state, with some of the worst poverty in the country.

Wyllys was one of seven children of illiterate parents. His home lacked electricity and drinkable water. He often went hungry and lost a sister to typhoid. At 10 he sold popcorn on the street for extra money, but he knew the value of education. He never left school and immersed himself in the extracurricular teachings of Catholic priests, who lent him books and taught him about social rights.

Wyllys is now a member of the Socialism and Liberty Party, which broke away from the governing camp and is pursuing a more radical agenda. It advocates greater spending on health and education and more action on behalf of marginalised communities. With a presidential election, a World Cup and possibly more protests, Wyllys expects 2014 to be a pivotal year in Brazilian politics after more than a decade of relative smooth sailing for the ruling Workers' Party.

He predicts tensions will mount between the two poles of Brazilian politics: a conservative camp of bankers, businesses, religious fundamentalists and those who miss the dictatorship that ended in 1985 – and a progressive camp comprising the LGBT movement, indigenous rights supporters and racial equality campaigners. "I expect to see greater radicalism and violence as the two forces come more to the fore," he says. "People want more than food and more than the consumer market; they want transparency in politics, transparency in public spending, less corruption between the state and private sector, and they want more participation in the political system."

Jean Wyllys is sworn in to Brazil's National Congress with fellow deputy former soccer player Romario in 2011. Photograph: Ueslei Marcelino/Reuters/Corbis

His views reflect the disillusionment some on the left feel 10 years after the Workers' Party took power. Luiz Inácio Lula da Silva won the presidency in 2003 with a promise to tackle inequality and corruption. But the government – now under his successor Dilma Rousseff – has been tainted by scandal and has had to make compromises that many supporters find unacceptable, including deals with politicians from the growing evangelical movement. These powerful right-wing groups are becoming more influential. One of their most outspoken representatives, the preacher Marco Feliciano, has declared Aids to be a "gay cancer" and Africans to be "cursed since the times of Noah". Despite this, he was appointed last year as president of the Commission for Human Rights and Minorities in Brazil's lower house of parliament.

"My fear is that Brazil will become a theocratic republic," Wyllys says. "I'm worried they could restrict liberties for ethnic, religious and sexual minorities." But he also sees opportunities in the coming 12 months which will put his country's politics and society under the spotlight like never before.

"Brazil is in a position where we have the potential to be a world leader, but we fall far behind in quality of education and health. We will only be able to lead if we can guarantee quality of life to our citizens." Pressing for such rights is likely to require a political fight.

"There are many senators and deputies who are homophobic," he says. "But they don't have the courage to openly discriminate against me because they know I'm prepared to defend against discrimination. My image demands respect."