Mrs. Kirchner, a driving force in the populist Kirchnerismo movement for two decades, denied the accusations, saying she is the victim of political persecution. She is expected to appeal the judgment, a process that Argentine legal experts say could drag on for years and hamper prosecutors’ efforts to ban her from holding office.

She might also never serve jail time because she enjoys immunity from prosecution. In addition, Argentine law prohibits prison time for people over 70 years old. Mrs. Kirchner turns 70 in February.

“This sentencing, my compatriots, is not one based on the laws of the constitution,” Mrs. Kirchner said in a video address just after the court’s decision. “This is a parallel state, a judicial mafia.”

Though Mrs. Kirchner had in the past left open another possible run for the presidency, she said on Tuesday following the sentence: “I will not be a candidate.”

“I won’t be a candidate for anything, not president, not senator,” said Mrs. Kirchner, who has also been a senator since 2019 and is considered the most dominant leader of her left-leaning political movement. “My name will not be on any ballot.”

The court also found eight others guilty of defrauding the state, sentencing them from three to six years in prison while acquitting four others. The case centered on the granting of public contracts to a construction mogul, Lázaro Báez, who was close to the Kirchner family.

As a powerful figure in President Alberto Fernández’s political coalition, Mrs. Kirchner’s legal troubles are likely to weigh on an unpopular government facing what economists call a challenging economic environment.

Mr. Fernández and his economy minister, Sergio Massa, agreed to austerity measures and cutting energy subsidies earlier this year as part of a deal with the International Monetary Fund to refinance $44 billion in debt to avoid a default. Mrs. Kirchner has opposed efforts to reduce the budget deficit, clashing with the president, while backing the printing of pesos to fund generous social programs.

Argentina’s poverty rate has risen, jumping from 28% in 2017 to 43% this year, according to a study by the Catholic University of Argentina. Annual inflation hit 88% in October, the government statistics agency said, tops in the Group of 20 and the highest pace of consumer price increases since Argentina faced hyperinflation in the early 1990s. And economists expect inflation to hit 100% by year’s end. The peso, meanwhile, has weakened sharply against the dollar this year, raising concerns about a painful devaluation amid low reserves at the Central Bank.

Mrs. Kirchner and her supporters say the investigation has generated animosity against her, leading to a purportedly failed assassination attempt in September after prosecutors formalized charges against her.

In a puzzling incident, a man thrust a gun in Mrs. Kirchner’s face as she greeted supporters outside her apartment and pulled the trigger. The weapon didn’t discharge, and the vice president was unharmed. A Brazilian man residing in Argentina was arrested immediately after the attack. Authorities haven’t disclosed a motive.

The criminal case against Mrs. Kirchner stems from her time as president, when the government granted highway building contracts to the construction magnate, Mr. Báez, in the southeastern province of Santa Cruz, a stronghold of Kirchnerismo.

Argentine antigraft prosecutors had sought 12 years in prison and a public-office ban, alleging that Mrs. Kirchner used her position to conspire with aides and Mr. Báez to receive kickbacks for fraudulent contracts for projects, some of which were never completed. The alleged conspiracy cost the government nearly $1 billion, prosecutors said.

While the court found Mrs. Kirchner guilty of defrauding the state, it didn’t find her guilty of leading a criminal conspiracy.

Mr. Báez, who is already serving a 12-year sentence on money-laundering charges, had in the past denied the allegations, showing off schools and other projects that he said demonstrated that the contracts issued to him were legitimate.

Mrs. Kirchner’s conviction is likely to further erode support for Mr. Fernández’s government, which has an approval rating of about 18%, according to Mariel Fornoni, director of Management and Fit, an Argentine political consultancy. In public-opinion surveys, corruption is topped only by inflation as citizens’ primary concern, said Ms. Fornoni.

In recent months, Mrs. Kirchner had criticized some of the Fernández administration’s efforts to reduce subsidies on gas and other utilities. Her comments, Ms. Fornoni said, had heightened speculation she would seek public office in elections next year, when Mr. Fernández’s term ends.

Mrs. Kirchner “has high levels of rejection” in polls, Ms. Fornoni said. But she said that the vice president also has had a base of strong supporters hovering at 25%, which until her announcement on Tuesday made her the leading figure in the ruling Peronist Party.

“It’s going to be hard to find anyone else to generate confidence in Argentina,” Ms. Fornoni said.

Mrs. Kirchner and her husband, Néstor Kirchner, president from 2003 to 2007, presided over the country during a tide of left-leaning governments across Latin America that used revenue from high commodity prices to ramp up public spending and forged alliances to counter the U.S. influence in the region.

With leftist governments again emerging in countries around the region, Mrs. Kirchner had a new bevy of allies, some of whom had criticized the investigation in Argentina.

In August, the presidents of México, Colombia and Bolivia joined Argentina in signing a joint statement calling the case against Mrs. Kirchner political persecution. “They’re trying to bury the ideals and values that she represents with the final objective to implant a neoliberal model,” the statement said.

In her comments after Tuesday’s verdict, Mrs. Kirchner cast the conviction as a ruling against the populist system she had furthered in Argentina. “They’re condemning me because they’re condemning a model of economic development and recognition of people’s rights,” she said.

Write to Kejal Vyas at kejal.vyas@wsj.com