Putin's remarks were made to foreign policy experts during a meeting in Sochi.
He said Russia had to invade Georgia after Georgia attacked South Ossetia's main city on Aug. 7.
If Russia had not invaded, Putin said, it would have been like Russia "getting a bloody nose and hanging its head down."
Putin also said Thursday that Russia has, "no wish or grounds to encroach on the sovereignty of former Soviet republics."
Prior to Putin's comments, Russia's foreign minister said South Ossetia does not want to become part of Russia.
Sergey Lavrov's statement Thursday followed a series of reports of contradictory statements by South Ossetian leader Eduard Kokoity.
Kokoity was quoted by news agencies as telling a group of foreign policy experts that South Ossetia would join Russia.
But he later retracted those comments in a subsequent interview with Interfax.
Lavrov later said during a visit to Warsaw that "South Ossetia doesn't wish to join up with anyone."
Russia and Georgia fought a short war last month and Russian annexation of Ossetia would infuriate the Georgians.
It would also give the impression that Russia had been seeking to absorb South Ossetia all along.
On Wednesday, shots fired near a Russian checkpoint outside South Ossetia killed a Georgian police officer, and police accused Russian forces of hindering their investigation.
The shooting on the tense line where Georgian authority ends underscored the threat of violence in the area, even as Russia begins to withdraw forces still deep in Georgia a month after a war.
In another show of defiance toward the United States, which has backed Georgia, Russia announced that twoon a training mission Wednesday.
Russia's Defense Ministry said in a statement that the planes will conduct training flights over neutral waters for a few days before heading back to Russia.
Russia had been angered that U.S. warships brought humanitarian aid to Georgia via the Black Sea, which Russia considers its sphere of influence. The flights appeared to be a direct challenge to the United States in its own hemisphere.
The Georgians did not return fire and the policeman later died at a hospital, he said.
At the headquarters of Russian forces in South Ossetia, a Russian official insisted that Russian troops did not fire the shots. The official said he was not authorized to give his name.
Georgian police official Vladimir Dzhukeli said the Russians had refused to let Georgian investigators pass through the Karaleti checkpoint to see where the gunfire might have come from.
Georgian media speculated that Russia's South Ossetian allies might have been the source of the gunfire, but a South Ossetia government spokeswoman insisted that was not the case.
Associated Press reporters have seen armed South Ossetians looting Georgian homes in the area since the war in early August, and ethnic Georgian refugees have accused some Ossetians of killings and beatings there.
Georgian authorities say about 2,000 Russian troops are posted at 24 positions ringing South Ossetia and Abkhazia and elsewhere in Georgia, a humiliating occupation.
On Wednesday, Georgian President Mikhail Saakashvili visited Gori, a central city near Karaleti that was targeted by Russian jets and tanks during the war. He reiterated his vow to restore control over South Ossetia and Abkhazia.
"We will do everything to restore Georgia's territorial integrity," Saakashvili told several dozen people outside a bombed-out apartment building that is being repaired. "That is our main task."
It's one that appears increasingly out of reach.
Under a deal reached by French President Nicolas Sarkozy on Monday, Russia pledged to withdraw its forces from all positions outside South Ossetia and Abkhazia within a month, after unarmed European Union observers are deployed.
But Russia said Tuesday it would keep 7,600 troops in the breakaway regions themselves for the foreseeable future, tightening its grip there.