Mr Yevkurov is a decorated Russian military officer
A career soldier has been appointed to run Russia's unstable southern republic of Ingushetia, where attacks on security forces have escalated.
Russian President Dmitry Medvedev named Yunus-Bek Yevkurov, a paratrooper, as acting president, to replace Murat Zyazikov, a former KGB officer.
He said he was not sacked and stepped down voluntarily, but the Kremlin accepted his resignation immediately.
Critics say Mr Zyazikov's crackdown did not work, and new tactics are needed.
The Kremlin seems to be admitting that it needs a new approach to ending the violence in the North Caucasus, the BBC's James Rodgers reports from Moscow.
Violence in the region is on the increase - raising the prospect of it spreading to other parts of the North Caucasus.
There are frequent attacks on officials and members of the security forces.
Ingushetia's armed insurgent groups are said to be linked to Islamist fighters in neighbouring Chechnya.
Mr Yevkurov was awarded the honour "Hero of Russia" for bravery in Chechnya, and was one of the commanders of the Russian contingent which seized control of Pristina airport during the Kosovo conflict in 1999.
In Chechnya, Russian forces were engaged in heavy fighting with separatist rebels until a few years ago, though the fighting has become much less intense recently.
Opposition groups in Ingushetia welcomed the departure of Murat Zyazikov, who stepped down on Thursday. He was appointed in 2002 by then-Russian President Vladimir Putin.
Mr Zyazikov defended his record by pointing to construction and development programmes he had initiated in Ingushetia.