Brazilian Federal Judge Sergio Moro sentenced Lula da Silva to nine-and-a-half years in jail. He will remain free during his appeal, and faces corruption, obstruction of justice and money laundering charges in four other court cases.
Wednesday's sentencing stems from a wide-ranging corruption investigation into the state-run oil company Petrobras, dubbed "Operation Car Wash."
The accusations against Lula da Silva emerged after he left office in 2011.
Moro said the former President benefited from the renovation of a triplex in a beach town near Sao Paulo by the construction company OAS.
The charges were connected to 3.7 million reais' ($1.1 million) worth of bribes received from OAS through the beachfront apartment. In return, Lula da Silva helped the builder acquire contracts from the oil company, the prosecutor's office said.
Lula da Silva, 71, strongly denied any wrongdoing. His defense said he was a victim of political persecution.
"The sentencing of former President Luiz Inacio Lula da Silva represents an attack on democracy and the Federal Constitution," Lula da Silva's Workers' Party said in a statement.
The party's statement said that the sentencing was carried out by a "partial judge, who is accountable to the media and to those who do not accept Lula's success story in the presidency."
"Today, more than ever, we stand in solidarity with Lula, and with his children and grandchildren," the statement said.
In his decision, Moro said the sentencing brought him no personal satisfaction and he found it "lamentable" that a former President had been criminally sentenced. He closed with Thomas Fuller's words: "Be you never so high the law is above you."
Universally known as Lula, Lula da Silva is a founding member of Brazil's only socialist political party, Partido dos Trabalhadores, the Workers' Party.
Born into a working class family, he left school and began working at age 12. Unhappy with the lack of political representation of the working class in Brazil, he decided to get involved in politics.
He won two terms as president, serving from October 2002 until January 2011. He was friends with the late Cuban leader Fidel Castro, who supported his political career, and attended Castro's funeral last December.
He left office with a 90% approval rating but was questioned by police about the corruption allegations in March 2016.
Da Silva's wife, Marisa Leticia Lula da Silva, and six others also was charged. She died in February.