Aleksei A. Navalny, an anticorruption activist who for more than a decade led the political opposition in President Vladimir V. Putin’s Russia while enduring arrests, assaults and a near-fatal poisoning, died Friday in a Russian prison, according to Russia’s Federal Penitentiary Service. He was 47.
The prison authorities said that Mr. Navalny lost consciousness on Friday after taking a walk in the Arctic penal colony where he was moved late last year. He was last seen on Thursday, when he had appeared in a court hearing via video link, smiling behind the bars of a cell and making jokes.
Kira Yarmysh, Navalny’s press secretary, said in a live broadcast Friday that Navalny’s advisers were not yet able to issue an official confirmation of his death but believed that he had perished. And while acknowledging that the United States did not know the details of what happened, President Biden at a White House news conference said, “Make no mistake: Putin is responsible for Navalny’s death.”
Mr. Navalny had been serving multiple sentences that would most likely have kept him in prison until at least 2031 on charges that his supporters say were largely fabricated in an effort to muzzle him. Despite increasingly harsh conditions, including repeated stints in solitary confinement, he maintained a presence on social media, while members of his team continued to publish investigations into Russia’s corrupt elite from exile.
Mr. Navalny was given a three-and-a-half-year prison sentence in February 2021 after returning to Russia from Germany, where he had been recovering from being poisoned the previous August. In March 2022, he received a nine-year sentence for embezzlement and fraud in a trial that international observers denounced as “politically motivated” and a “sham.” And in August 2023, he was sentenced to 19 years in prison for “extremism.”
Mr. Navalny had effectively returned from the dead after he was poisoned with a nerve agent in Siberia in 2020, and he conducted multiple hunger strikes to improve his treatment. During his detention, Mr. Navalny was repeatedly placed in solitary confinement and complained about severe illnesses. In December, he disappeared for three weeks during his transfer to a penal colony 40 miles north of the Arctic Circle.
Yet even from prison, Mr. Navalny remained an unflinching critic of Mr. Putin, a former K.G.B. officer whom he accused of corruptly skimming the country’s oil profits to enrich his friends and entourage in the security services. Mr. Putin’s political party, he once said, was a party of “swindlers and thieves,” and he accused the president of trying to turn Russia into a “feudal state.”
His own politics evolved as he sharpened his criticism of Mr. Putin. While Mr. Navalny did not outright condemn the annexation of Ukraine’s Crimean peninsula by Russia in 2014, for example, he was unabashedly critical of Russia’s full-scale invasion of Ukraine two years ago.
In November 2022, Mr. Navalny called the invasion a “nightmare” that Russia had been pulled into by Mr. Putin, whom he labeled “a single crazy grandfather who lives in fantasies that he is a military leader, unusually popular in Ukraine.”
Mr. Navalny was known for his innovative tactics in fighting corruption and promoting democracy. Defying expectations, he cannily used street politics and social media to build a tenacious opposition movement even after much of the independent news media in Russia was squelched and other critics were driven into exile or killed in unsolved murders. In the years before Russia invaded Ukraine, many of Mr. Navalny’s associates, and in some cases their relatives, were arrested or forced into exile.
At his death, he was the most prominent critic of Mr. Putin still standing in Russia, at a time when the president has engineered a path to remain in power until at least 2036.
He had spoken openly of the possibility that he might be assassinated.
“I’m trying not to think about it a lot,” he said in an interview with CBS News in 2017. “If you start to think about what kind of risks I have, you cannot do anything.”
On Aug. 20, 2020, Mr. Navalny became violently ill and fell into a coma shortly after boarding a flight from Siberia, where he had met with opposition candidates for local office.
The flight made an emergency landing in the Russian city of Omsk, where doctors for two days resisted his wife’s pleas that he be transferred to Germany for treatment.
Mr. Navalny was eventually evacuated to Berlin on an air ambulance flight after a team of German doctors who had arrived in Omsk stated that it was safe for him to travel. A little more than a week later, the German government announced that he had been poisoned with a nerve agent from the highly potent Novichok family of toxins. The evidence, German officials said, was “unequivocal.”
“Mr. Navalny has been the victim of a crime,” Chancellor Angela Merkel of Germany said at the time. “It raises very serious questions that only the Russian government can and must answer.”
Novichok, a Soviet-era weapon invented for military use, was used against Sergei V. Skripal, a former Soviet spy, and his daughter in a 2018 attack in Salisbury, England, that the British government attributed to Russia’s military intelligence arm, the G.R.U.
In December 2020, Mr. Navalny released a video of himself — posing as an aide to a senior Russian security official — extracting a confession from one of his would-be assassins, essentially confirming the involvement of the Russian secret services. He was told that the poison had been planted in his underwear at his hotel sometime before he boarded the plane.
The following month he flew back to Russia, facing an all-but-certain prison sentence. He was arrested at the airport but his return breathed new life into the Russian opposition, and protests broke out across the country.
Within days of his return, his team released a report about a purported secret palace built for Mr. Putin that was viewed more than 100 million times on YouTube, helping to fuel the protests. At his 2021 sentencing, speaking from a Moscow courtroom, Mr. Navalny predicted that Russians would eventually rise and prevail against Mr. Putin, whom he called “a thieving little man.”
Russian officials had previously deployed a low-level campaign of harassment against Mr. Navalny. He was frequently arrested and jailed for short spells, usually for minor offenses related to protesting without a parade permit.
Mr. Putin barely mentioned Mr. Navalny’s name, and the state news media steadfastly ignored him throughout his decade-long anticorruption campaign. Yet Mr. Navalny, a young, scrappy politician, found a base of support in the Russian middle class, and that clearly irritated the Kremlin.
Dismissing him as an unpatriotic gadfly, the Kremlin at times seemed willing to overlook his criticisms to give Mr. Putin the veneer of running a government that tolerated dissent. The short detentions allowed the Russian authorities to keep Mr. Navalny out of sight for important events, like organized protests, while escaping criticism for harsh treatment that might make him a martyr.
Despite the attacks and the jail terms, Mr. Navalny persevered, he said, out of a desire to change the course of his country and not let down the people who worked with him. He was angry at what he called Mr. Putin’s self-dealing inner circle and the security services that protected it.
“I do this because I hate these people,” he said in an interview with The New York Times in 2011, before he rose to prominence.
Still, he struggled to unite the feuding pro-democracy opposition parties, a fractured state of affairs that has plagued Russia’s politics since the breakup of the Soviet Union in 1991.
Some were wary of his right-wing positions, like the Russian nationalism that characterized his early political activities, his support for gun rights and his anti-immigrant views.
Aleksei Anatolievich Navalny, the son of a Red Army officer, was born on June 4, 1976, in Butyn, a village near Moscow, and grew up on far-flung military bases throughout the former Soviet Union.
Mr. Navalny studied law at the Peoples’ Friendship University in Moscow and economics at the Finance Academy of the Russian Federation. He worked as a real estate lawyer before going into politics, first gaining recognition as the author of a blog for small investors that exposed signs of theft and abuse inside some of the country’s giant state-owned companies, like Gazprom and Rosneft.
While the blog’s purpose was financial — to advocate for minority shareholders — it was also politically daring, because it accused government insiders of abuse and Mr. Putin of tolerating that abuse.
Mr. Navalny’s support among the middle class — mostly in the capital, Moscow, where he ran unsuccessfully for mayor in 2013 — brought a new type of politics to the country, one focused not on the woes of striking miners or the aloof intellectual class but on bread-and-butter issues of the new capitalist era, like protecting home equity and investments in stocks.
Social media outlets like Twitter, now rebranded as X, and Vkontakte, a Russian analogue to Facebook, propelled Mr. Navalny’s rise. A breakthrough came in 2011, when he used social networking sites to promote street protests opposed to Mr. Putin’s return to power for a third presidential term. The protests breathed new life into a beleaguered opposition, and he came to be seen as the movement’s leader.
Years of arrests and attacks followed.
Initially, prosecutors pressed charges of embezzlement — related to his work as an adviser to a regional governor years before — that were widely seen as politically motivated. Mr. Navalny received a five-year suspended sentence.
Mr. Navalny continued to speak out. Barred from running for office because of his criminal convictions, he promoted other opposition politicians and ran an anticorruption group that turned out devastating reports of high-level graft.
In one searing exposé in 2017, he laid out a web of foundations and shell companies, all connected to former President Dmitri A. Medvedev, whose mansions, country estates, 18th-century palace in St. Petersburg and vineyard in Tuscany were displayed in the video.
“The system has turned so rotten that it doesn’t have any healthy parts at all,” Mr. Navalny said.
Mr. Navalny was detained so many times that he once joked to a judge that he wouldn’t take up the court’s time with a final statement before sentencing, because he would surely have another chance to do so again.
“The last word of the accused should be a dramatic moment in his life,” he said. “But they opened so many cases against me that this will not be my last chance to have a last word.”
Mr. Navalny met his wife on a beach in Turkey 23 years ago and, before the poisoning in 2020, the couple lived in a three-room apartment in an outlying district of Moscow. Ms. Navalnaya has an economics degree and worked at a bank before the birth of their children. She has over the past decade been a homemaker and, as pressure on Mr. Navalny increased, became more outspoken about his poor treatment.
Like her husband, Ms. Navalnaya and other members of his family have lived for years in a crucible of surveillance and police pressure. Oleg Navalny was sentenced to three and a half years in prison in 2014 on what were widely regarded as trumped-up fraud charges intended to halt his brother’s political activities. Mr. Navalny’s parents and grandparents have been “harassed and unlawfully prosecuted many times,” his daughter wrote in Time magazine in December 2022.
The family was often seen by observers as a foil for that of Mr. Putin, who is divorced and is rarely seen in public discussing his children. Mr. Navalny dedicated his final post on social media to his wife on Valentine’s Day.
“Darling, everything is like in the song with you: between us there are cities, the lights of airfields, blue snowstorms and thousands of kilometers. But I feel that you are near every second, and I love you more and more,” he wrote on Telegram, ending his post with a heart emoji. The song he quoted, “Hope, my earthly compass,” is one of the best-known hits in Russia. Its refrain is “Hope is my compass, and success is a reward for courage.”