Yevgeniy Prigozhin, Russian mercenary leader who became Putin foe

Putin appeared to acknowledge Mr. Prigozhin’s death in televised remarks Aug. 24, when he expressed his condolences to the families of the people killed in the crash. Mr. Prigozhin’s name had appeared on the plane’s manifest. Putin spoke of Mr. Prigozhin in the past tense, describing him as “a man of complex fate” who “made serious mistakes in his life.”

The U.S. intelligence community believes Mr. Prigozhin “likely” died in the crash and is exploring the possibility an explosion brought down his plane.

In an ascent that he owed almost entirely to the favor of Putin, his longtime patron, Mr. Prigozhin represented an unlikely case study in rebellion.

For years, he was denounced by the West as a Kremlin henchman and hailed by Russian state media as a patriot. With his weathered features and bulldog demeanor, he fit well into both narratives.

His guns-for-hire private military company, the Wagner Group, sent fighters across the Middle East and Africa to bolster Russian interests — and Mr. Prigozhin’s own agenda — often in brutal fashion. He attacked in cyberspace as well, running a troll factory that roiled Western elections and bankrolling efforts to plant fervently nationalist, pro-Kremlin views in social media.

Mr. Prigozhin (pronounced pree-GOH-zhin) first crossed paths with Putin in Russia’s post-Soviet bacchanal of excess in the 1990s. After serving nearly a decade in prison for robbery, Mr. Prigozhin opened a family-run hot dog stand that made him flush with rubles. He went into a casino venture, then joined with other investors to open the hottest restaurant in St. Petersburg.

The restaurant, New Island, became a favorite haunt for Putin, a former KGB officer who then served as a top aide to the city’s mayor. Putin liked Mr. Prigozhin’s swagger. Mr. Prigozhin admired Putin’s status and connections. They both were supremely ambitious.

As Putin climbed to power — starting in 1999 when he became prime minister under President Boris Yeltsin — favors started to flow Mr. Prigozhin’s way. First came lucrative food service contracts with schools and the military for Mr. Prigozhin’s catering company, Concord, earning him the nickname “Putin’s chef.”

Putin then cleared the way for Mr. Prigozhin’s mercenary corps. In the calculation of the autocratic president, Mr. Prigozhin was a useful opportunist with a ruthless streak.

He occupied an unparalleled role. His militiamen helped carry out Russian objectives by backing shaky foreign governments and nailing down mineral rights and other concessions. Wagner and its founder were enriched by cuts from the money flow and side deals.

Western leaders and rights groups long saw Mr. Prigozhin as Putin’s shadowy enforcer — a capo in camouflage allegedly linked to potential war crimes. Because Wagner was portrayed as a private group, it offered a political shield for the Kremlin for messy practices such as targeting opposition in Russia-friendly states including Mali and the Central African Republic.

In 2023, Putin acknowledged what was widely suspected: Wagner was a full-fledged arm of the Kremlin, receiving as much as $1 billion in state funds during the first year of the Ukraine war.

When Russia invaded Ukraine in February 2022, Putin’s predictions of a lightning victory were quashed by Ukraine’s unflagging resistance and a surge of Western military aid.

Mr. Prigozhin saw the conflict as his chance to make history by turning the tide for beleaguered Russian forces.

His fighters, among them prisoners recruited from Russian prisons, made some immediate gains in early 2023 with tactics that were savagely efficient. In fast-moving assaults, the former inmates often led the charge as expendable fodder. “I’m taking you alive,” a Wagner video recruiting pitch to prisoners declared. “But I don’t always return [you] alive.”

Wagner advances, although temporary in some places, were a rare bit of good news for Putin. But his alliance of convenience with Mr. Prigozhin soon began to show fissures.

In a country where dissidents are often the target of suspected state-ordered hits, Mr. Prigozhin stood apart with his public outbursts over what he called the Kremlin’s inept military planning and flawed tactics.

Mr. Prigozhin’s growing frustration exploded late on June 23, when he and Wagner forces left Ukraine and swept into the southern Russian city of Rostov-on-Don, seizing military headquarters and effectively taking two generals captive.

The next morning, he sent Wagner tanks and personnel carriers rolling toward Moscow. Wagner gunners brought down Russian helicopters and a military surveillance plane. A panicked Putin denounced the “armed mutiny” as the world watched, stunned, amid the unprecedented challenge to his strongman rule.

A fast-hatched intervention conveyed by a Putin ally, Belarusian authoritarian leader Alexander Lukashenko, kept the crisis from growing. “Prigozhin was a monster Putin created and allowed to grow,” said Ariel Cohen, a Russia analyst at the Atlantic Council think tank’s Eurasia Center. “It’s a timeless lesson: Be careful what you wish for.”

For embarrassing him on a global scale, Putin took systematic revenge, dismantling much of Wagner. Russian state media, meanwhile, broadcast images intended to discredit Mr. Prigozhin’s commando persona, including of the mercenary leader in wigs and crude disguises, such as an Islamist-style beard and wraparound sunglasses.

Yet Putin and Mr. Prigozhin also looked for some way to coexist. They met secretly, along with a group of Wagner militiamen, five days after Mr. Prigozhin’s revolt.

After weeks of silence on the details of the meeting, Putin insisted that Mr. Prigozhin was neutralized. “Wagner does not exist,” Putin told the Russian business newspaper Kommersant. Putin praised the Wagner fighters for their Ukraine battles and said they could remain as an auxiliary-style unit in the Russian military — but not under Mr. Prigozhin’s command.

Yevgeniy Viktorovich Prigozhin was born in what was then Leningrad (later known by its pre-revolution name, St. Petersburg) on June 1, 1961. His mother was a hospital nurse who remarried after the death of her husband when Mr. Prigozhin was young. His stepfather was a coach at a sports academy, which offered a spot to Mr. Prigozhin as a promising cross-country skier.

He did not make the cut to become a professional in the Soviet sports system. After leaving the academy in 1980, Mr. Prigozhin fell in with street gangs and was arrested for small-time thefts as a juvenile. At 18, he was convicted of taking part in the robbery of a woman on a Leningrad street.

Mr. Prigozhin “grabbed her neck, squeezing until she lost consciousness,” according to the Guardian, citing official documents made public by the Russian investigative news site Meduza. One attacker took her shoes, while Mr. Prigozhin “deftly removed her gold earrings.”

He was in prison until 1990, returning to a city that was rapidly changing under the reforms of Soviet leader Mikhail Gorbachev. Mr. Prigozhin enjoyed success with his mother and stepfather as hot dog vendors as fast food became synonymous with the new times. He rolled the profits into a casino investment.

In 1995, Mr. Prigozhin and a business partner opened their first restaurant, Staraya Tamozhnya, or the Old Customs House, serving French cuisine. Two years later, the floating New Island restaurant, created from a rusting ship, opened its doors. More restaurants with ties to Mr. Prigozhin followed in Moscow.

Mr. Prigozhin played maitre d’ in St. Petersburg as Putin — who loved to show off his home city — dined in 2001 with French President Jacques Chirac and President George W. Bush in 2006. British royalty also stopped by New Island, including the future King Charles III.

It was Putin’s obsession with Ukraine, and what was lost in the 1991 Soviet collapse, that made Mr. Prigozhin exchange his dinner jackets for fatigues.

Mr. Prigozhin and a group of Kremlin insiders started to assemble a mercenary force shortly after Putin’s land grab of Crimea from Ukraine in 2014. A year later, Wagner was part of Russia’s military surge into Syria to aid its embattled ally, Syrian President Bashar al-Assad, amid a civil war and threats from the Islamic State extremist group. Wagner units protected Syria’s oil fields and, as compensation, received a slice of Syria’s petrodollars, according to Western officials.

As long as Putin felt he could count on Mr. Prigozhin, Wagner was allowed to grow, reaching an estimated 50,000 fighters at its peak. Mr. Prigozhin’s personal fortune swelled, too, elevating him to billionaire status, with playthings such as a 122-foot yacht, St. Vitamin.

For years, Mr. Prigozhin refused to even acknowledge his ties to Wagner. Finally, in September 2022, he publicly embraced his role as a Wagner founder. (The name is believed to be inspired by a Wagner leader, former Russian military officer Dmitry Utkin, as an homage to German composer Richard Wagner, whose music was favored by Adolf Hitler. Utkin was also on the manifest of the crashed plane.)

Mr. Prigozhin was linked by U.S. officials to the Internet Research Agency, a St. Petersburg-based group accused of being a hub for bogus social media accounts, fake news and other efforts to disrupt elections, including the 2016 U.S. presidential race.

In the post-election report overseen by special counsel Robert S. Mueller III, a former FBI director, one section described how Internet Research Agency trolls in Russia, posing on Facebook as right-wing activists based in the United States, persuaded a protester in 2016 to stand in front of the White House with a sign that read “Happy 55th Birthday, Dear Boss” to coincide with Mr. Prigozhin’s birthday.

The Justice Department in 2018 indicted Mr. Prigozhin, the Internet Research Agency and others on charges of interfering with the 2016 U.S. presidential election. (The case was dropped in early 2020 over worries it could expose classified material.)

Mr. Prigozhin basked in the accusations. “We have interfered, we are interfering and we will continue to interfere,” he said in 2022. After the FBI put Mr. Prigozhin on its most-wanted list and the Treasury Department placed him under additional sanctions, Mr. Prigozhin seemed unfazed.

“Americans are very impressionable people,” he was quoted telling the RIA Novosti news agency at the time. “They see what they want to see. … If they want to see the devil, let them see him.”

Mr. Prigozhin’s death does not close the books on international probes into alleged Wagner atrocities.

In early 2023, United Nations investigators called for probes into possible war crimes by government forces and Wagner Group units in Mali. In designating Wagner a “transnational criminal organization” in January, the Treasury Department imposed sanctions on Wagner-related businesses and accused Wagner personnel of engaging “in an ongoing pattern of serious criminal activity, including mass executions, rape, child abductions, and physical abuse in the Central African Republic and Mali.”

Mr. Prigozhin was married to Lyubov Valentinovna Prigozhina. They had two children — a daughter, Polina, and a son, Pavel — but a complete list of survivors was not immediately available.

In light of the range of his activities, Mr. Prigozhin sometimes wondered why he was dubbed “Putin’s chef.” He preferred another moniker.

“Putin’s butcher,” he said in an interview posted to his Telegram channel, “and everything would have been fine.”