Who is Yevgeny Prigozhin, the mercenary leader Russia accused of mounting a coup?

Yevgeny V. Prigozhin became rich through his personal ties to President Vladimir V. Putin of Russia, winning lucrative catering and construction contracts with the Russian government while building a mercenary force known as Wagner.

After Russia’s invasion of Ukraine, he threw his fighters into the fray, as their ranks swelled with prisoner recruits. In recent months, Mr. Prigozhin (pronounced pree-GOH-zhin) has also emerged as a public power player, using social media to turn tough talk and brutality into his personal brand. At the same time, though, he began launching accusations at Russia’s military leadership, blaming it for failing to provide his forces with enough ammunition and ignoring soldiers’ struggles.

But until Friday — when Russian generals accused Mr. Prigozhin of mounting a coup — Mr. Putin had not checked Mr. Prigozhin’s online accusations, despite jailing or fining many other critics of the war.

Spewing vulgarities, disregarding the law and displaying loyalty to no one but Mr. Putin, Mr. Prigozhin, a businessman known as “Putin’s chef” because of his catering contracts with the Kremlin and Russian military, has become a symbol of wartime Russia: ruthless, shameless and lawless. It was a significant turnabout for Mr. Prigozhin, who acknowledged only last fall that he had founded Wagner.

In Moscow, he has been dogged by open questions and criticism, with analysts expressing doubts that his recruitment of prisoners and endorsement of extrajudicial executions had broad appeal.

Mr. Prigozhin expanded Wagner’s presence in Ukraine after the Kremlin’s attempt to seize Kyiv, the capital, failed in the initial days of its invasion early last year. The “private military company” was at that point largely active in Syria and Africa, where it operated both on behalf of the Russian government and in the service of Mr. Prigozhin’s own business interests.

He was also active elsewhere. In February 2018, Mr. Prigozhin was one of 13 Russians indicted by a federal grand jury for interfering in the American election through the Internet Research Agency, a troll factory that spread falsehoods and waged information warfare against the United States, in support of the presidential campaign of Donald J. Trump.

The United States imposed sanctions against Mr. Prigozhin in December 2016.

Born in 1961 when St. Petersburg was called Leningrad, Mr. Prigozhin was sent to prison in 1981 for robbery and other crimes, according to Meduza, an online investigative publication.

After serving his nine-year sentence, he opened a hot-dog stand, eventually leading to an entrepreneurial career starting restaurants and convenience stores.