The top opposition contender in Tuesday's presidential race, Sata casts himself as a man of action and has promised to transform the poor southern African country's fortunes within 90 days.
"Lower taxes and more money in your pocket" has become a chorus among poor Zambians who flock to huge rallies to listen to Sata, seen by many as a potential saviour in a country where 64% of the population lives on less than two dollars a day.
His campaign symbol is a boat that resembles Noah's Ark, and he parades through the streets in a speedboat pulled on a trailer, telling Zambians to jump on board to be saved from poverty and under-development.
But at 74, the heart attack survivor and former chain smoker is beginning to show his age - more so than his fellow 74-year-old and top rival, President Rupiah Banda.
Sata has little formal education, but presents himself as an experienced leader who served with distinction in various government ministries before quitting the ruling Movement for Multi-party Democracy to form the breakaway Patriotic Front in 2001.
Sata thrives on controversy. During the 2008 special elections following the death of late president Levy Mwanawasa, he raised dust and alarmed investors by promising to force foreign companies to grant a minimum 25 percent stake to locals within 30 days of taking office.
"A friend of thieves"
Critics fear the strong-fisted firebrand would make an authoritarian president.
But he has toned down some of his rhetoric from previous campaigns, when he threatened to expel the Chinese investors who have flocked to Zambia's copper mining sector - the largest in Africa, and one of the world's top 10 - amid rising international prices.
Sata now says he will work with Chinese investors if elected.
He did, however, lash out forcefully at China's heavy presence last year after two Chinese mine managers in the southern Zambian town of Sinazongwe allegedly shot and wounded 11 workers for protesting over poor labour conditions.
"Can a Zambian shoot a Chinese in China and be left scot free? This is what we have allowed to happen in Zambia," he told AFP.
But this year he has largely replaced his anti-Chinese platform with accusations that Banda is soft on corruption, after the government failed to appeal the graft acquittal of former president Frederick Chiluba and disbanded the anti-corruption unit that accused the ex-leader of stealing public funds.
"Banda is a friend of thieves and thieves are very free. They have more independence than you people," he told a recent campaign rally.
Sata has launched a slogan called "Don't Kubeba" - meaning "Don't Tell" - that encourages voters to accept Banda's handouts of free electricity and other campaign-season gifts but vote for Sata on election day.
Fourth presidential bid
An open admirer of Zimbabwe's President Robert Mugabe, Sata has had a lengthy career in politics, serving as minister of local government, labour, and health.
He eventually became minister without portfolio, the third-highest post in government.
He also served as governor of the capital, Lusaka, under Zambia's first president, Kenneth Kaunda, but quit in 1991 when the country introduced multi-party politics.
He has a large family with his wife, Christine Kaseba.
This is his fourth presidential bid, having been trounced twice by Mwanawasa in 2001 and 2006, and losing narrowly to Banda in 2008.
He claims the last election was rigged, and his supporters rioted for days to protest his loss.