Teodoro Petkoff, shown in 2006, was celebrated as a critical thinker who maintained his political independence within an opposition movement. (Juan Barreto/AFP/Getty Images)

Teodoro Petkoff, a giant of Venezuela’s politics who led a band of communist guerrillas in his youth before winning the praise of Wall Street in a top government post and then launching a newspaper that fearlessly railed against socialist President Hugo Chávez, died Oct. 31 in Caracas. He was 86.

Xabier Coscojuela, editor of the newspaper Tal Cual, confirmed the death. The cause was not disclosed.

Mr. Petkoff was celebrated as a critical thinker who maintained his political independence within an opposition movement weakened by cronyism and infighting. In later life, he promoted conservative economic policies, which some of his early leftist friends considered a betrayal.

“Teodoro Petkoff was a mentor to at least three generations of Venezuelans. I count myself among them,” playwright, essayist and former Tal Cual columnist Ibsen Martínez told the Associated Press. “He instilled in us the idea that democracy and tolerance . . . are the essence of social justice.”

Mr. Petkoff’s life story was marked by daring prison escapes, bank heists and failed presidential campaigns in the tumultuous South American petro state.

Teodoro Petkoff Malec was born Jan. 3, 1932, in Bobures, Venezuela, to a Bulgarian father and Polish mother of Jewish origin who had immigrated to Venezuela.

Mr. Petkoff was “the greatest democrat of the left in Latin America,” said Enrique Krauze, a Mexican historian. (Juan Barreto/AFP/Getty Images)

He began his political rise as a student leader. He then joined the Communist Party and took up arms in the 1950s against dictator Marcos Pérez Jiménez.

Inspired by the revolution of Fidel Castro in Cuba, Mr. Petkoff and others joined a guerrilla movement and carried out actions that included the kidnapping of a U.S. colonel.

Mr. Petkoff spent three years in prison and escaped twice, once by slipping through a tunnel onto the streets of Caracas, where large crowds of costumed Carnival-goers provided ample cover.

In a second escape, he vomited blood that he had swallowed to feign illness and gained access to a prison hospital, where he rappelled down by rope from a seventh-story window.

Mr. Petkoff continued an armed insurgency against a U.S.-backed democratic government that replaced Pérez Jiménez in 1958. The rebels robbed banks, kidnapped business executives and fought at times with soldiers.

He turned to journalism in the mid-1960s, writing for the Communist Party’s newspaper in Caracas.

But the movement faded in the 1970s as then-President Rafael Caldera offered amnesty to the last remaining rebels. By then, Mr. Petkoff had grown disillusioned with the Soviet model, which he increasingly viewed as authoritarian.

Together with other former rebels, he formed the left-leaning Movement Toward Socialism and was elected to the Senate. He ran for the presidency twice in the 1980s and was handily defeated both times.

He joined the government in the late 1990s when Caldera tapped him as planning minister during an economic crisis. Mr. Petkoff won praise on Wall Street for privatizing state-run companies and cutting subsidies while gradually reducing the state’s role in the economy.

His wit was put on display when he launched Tal Cual in 2000 during the rise of Chávez’s socialist movement, which maintains power today. The newspaper’s inaugural front page boldly called out to the charismatic president with the headline: “Hola, Hugo.”

Tal Cual’s edgy stories and cutting opinion pieces over the years have drawn criticism from the government, including a defamation lawsuit filed by socialist party boss Diosdado Cabello, then president of the National Assembly. It was later dropped.

Mr. Petkoff’s third presidential bid came in 2006 in a challenge to Chávez, who ultimately won a second six-year term. Chávez was reelected in 2012 but died a year later at age 58.

Mr. Petkoff was “the greatest democrat of the left in Latin America,” said Enrique Krauze, a Mexican historian and conservative critic of Venezuela’s socialist government.

Luis Almagro, secretary general of the Organization of American States, said Mr. Petkoff’s death is a loss that extends beyond his native Venezuela.

“He leaves Venezuela and the region without a mandate on social commitment, political coherence and defense of democratic values,” Almagro said on Twitter. “His struggle for freedom of expression and defense of human rights will never be forgotten.”

Information about survivors could not be confirmed.