With close to half of the ballots counted on Sunday evening, Mr. Correa had received 56 percent of the votes cast, according to news media in Ecuador. Guillermo Lasso, a banker, the closest of his seven opponents, had 24 percent.
Thousands of supporters in the main square in Quito, the capital, began celebrating shortly after voting finished at 5 p.m., when television stations announced the result of exit polls showing Mr. Correa as the runaway winner.
“Many thanks for this immense trust,” Mr. Correa said from the balcony of the presidential palace. “We have never failed you, and we never will fail you.”
Critics of Mr. Correa have worried that such a strong mandate would embolden him to further concentrate power and proceed with policies that could limit press freedom and quash dissent.
Following the re-election last fall of President Hugo Chávez in Venezuela, Mr. Correa’s victory ratified the lasting appeal in the region of leftist governments that have used revenues from booming oil and mining industries to finance social welfare programs aimed at redistributing wealth and curbing inequality.
Now, with Mr. Chávez battling cancer, Mr. Correa could raise his profile as one of the most vocal leaders on the Latin American left.
Mr. Correa told reporters that he would continue policies aimed at ending poverty and diminishing inequality, saying the challenge of the next four years “is go faster and deeper in the same direction.”
His victory also highlighted the weakness of the political opposition in Ecuador. He faced a raft of opponents from across the political spectrum who split the vote from a fractured opposition that was unable to coalesce behind a single candidate or project a unified message.
Mr. Correa also won points from voters for bringing stability to Ecuador, a country that had seven presidents in the decade before he took office and was buffeted by severe economic problems. According to the new Constitution that was passed at his urging in 2008, Mr. Correa cannot run again when his new term ends in 2017.
Mr. Correa, an economist who studied at the University of Illinois, has improved access to education and health care for the poor and has built or improved thousands of miles of roads and highways. In a new term, he has pledged to continue signature social programs and to pass laws covering the news media, land reform and the penal code.
But he has governed with aggressive tactics that critics say undermine democracy by expanding presidential power; weakening the independence of the courts; and lashing out often at perceived enemies, including political opponents, the media and, at times, the United States.
“You have to trust Correa because he has done a lot that other governments never did in all these years,” said Rita Bastidas, a 42-year-old nurse, after voting for the president in the south of Quito. “Correa came along, and, in very little time, everything changed for the better.”
She added, “They accuse him of being authoritarian and arrogant, but this country needed someone like that to change things.”
An employee at the Ministry of Health said he voted against Mr. Correa because he did not like the way the president managed the health system, adding that qualified personnel had been pushed into retirement and replaced by members of Mr. Correa’s party.
“I want better days where they govern for everyone and not just for the greens,” he said, referring to the color used by the president’s party, Alianza País. The man spoke anonymously because he feared reprisals at work if it were known that he voted against the president.
Domingo Paredes, the president of the National Electoral Council, said Sunday that officials had detected an attack on electoral computer systems but that it was not successful.
Maggy Ayala contributed reporting from Quito, Ecuador.
