Charismatic ex-steelworker Luiz Inacio Lula da Silva rose from poverty to become the most popular president in Brazilian history, only to fall spectacularly from grace when he was jailed for corruption.

Now, capping a lifetime of dramatic twists of fate, the 76-year-old leftist icon is seeking his unlikeliest turnaround yet: a presidential comeback.

Lula, who is due to officially launch his campaign Tuesday, will seek to stop his nemesis, far-right President Jair Bolsonaro, from winning a new term in Brazil's October elections.

Known for his political skill and folksy touch, Lula left office on January 1, 2011 as a blue-collar hero who presided over a watershed boom and helped lift tens of millions of people from poverty.

But he then became embroiled in a massive corruption scandal that engulfed some of Brazil's most influential politicians and business executives.

Lula was controversially jailed in 2018, removing him as the favorite in that year's presidential race -- which Bolsonaro won.

He spent more than 18 months in prison before being freed pending appeal.

Then, in March last year, Brazil's Supreme Court annulled his convictions, ruling there was bias on the part of the lead judge in the case, Sergio Moro, who had gone on to become Bolsonaro's justice minister.

The ruling landed like a bomb just as Brazil geared up for this year's elections.

Loved and hated with roughly equal passion in Brazil, Lula has been the front-runner in opinion polls ever since.

Brazil's first working-class president, Lula enjoyed widespread popularity during his two terms, when a commodity-fueled economic boom helped him ride out numerous corruption scandals.

Under his administration, which mixed trailblazing social programs with market-friendly economic policy, some 30 million people rose from poverty in Brazil, where inequality is among the world's worst.

Lula also turned Brazil into a key player on the international stage, helping bring it the 2014 World Cup and 2016 Olympics in Rio de Janeiro.

Called "the most popular politician on Earth" by no less than Barack Obama, he stepped down after eight years basking in 87 percent popularity ratings.

But just as he settled into the role of elder statesman, he was clobbered by "Operation Car Wash," the sweeping investigation that uncovered a massive web of corruption centered on state-run oil company Petrobras.

Prosecutors struggled to prove their claim Lula masterminded the scheme. But he was sentenced to a total of 26 years on charges of accepting a triplex beach apartment and renovations at a ranch property as bribes for greasing companies' access to juicy Petrobras contracts.

He has always denied the accusations against him, alleging a plot to sideline him and his Workers' Party (PT).

Lula grew up in deep poverty, the seventh of eight children born to a family of illiterate farmers in the arid northeastern state of Pernambuco.

When he was seven, his family joined a wave of migration to the industrial heartland of Sao Paulo state. Lula worked as a shoeshine boy and peanut vendor on the street, before becoming a metalworker at age 14.

In the 1960s, he lost the little finger of his left hand in a workplace accident.

He rose quickly to become head of his trade union, and was the force behind major strikes in the 1970s that challenged the military dictatorship then in power.

In 1980, he co-founded the Workers' Party, standing as its candidate for president nine years later.

Lula made three unsuccessful bids for the presidency, from 1989 to 1998, each time chipping away at the establishment notion that a poor, uneducated laborer could never lead Brazil.

The fourth time, in 2002, he succeeded, taking office on January 1, 2003, and winning re-election in 2006.

He is hoping to repeat that success this year, his sixth presidential campaign.

His wife of four decades, Marisa Leticia Rocco, died of a stroke in 2017.

In his trademark gravelly voice, Lula says he is now "in love as if I were 20 years old" with Rosangela "Janja" da Silva, a sociologist and Workers' Party activist, whom he married in May.