But the whereabouts of the convicted man, Alexei Moskalyov, were unclear. The court said in an official posting on VKontakte, similar to Facebook, that he had fled from house arrest.
Moskalyov has been separated from his 13-year-old daughter Masha since he was placed under house arrest at the start of this month and she was moved to a children's home in their hometown of Yefremov, south of Moscow.
The case has provoked an outcry among Russian human rights activists and sparked an online campaign to reunite father and daughter.
Moskalyov's lawyer Vladimir Biliyenko said he had not seen his client since Monday and did not know whether Moskalyov had fled, as he had only the spokesperson's statement to go by.
"At the moment, to be honest, I'm in a state of shock," he told Reuters.
He added that the defence would appeal against the verdict and Masha would remain in the children's home for the time being.
Yevgeny Prigozhin, the founder of Wagner Group, Russia's most powerful mercenary group involved in some of the fiercest fighting in Ukraine, called the verdict "unfair" and asked that it was reviewed.
"Especially in view of the fact that his daughter Masha will be forced to grow up in an orphanage," Prigozhin wrote in a letter to the prosecutor of the case and published on his press service's Telegram platform.
In a joint appeal with lawyers associated with Wagner, Prigozhin called for the lawyers to be allowed to work for the defender.
"We are waging a war against evil for the sake of the future of our children," he said.
Moskalyov was convicted over comments he himself had posted online about the war in Ukraine. But the investigation started after Masha, then 12, drew a picture last April showing Russian missiles raining down on a Ukrainian mother and child, prompting the head of her school to call the police.
The drawing featured a Ukrainian flag with the words "Glory to Ukraine" and a Russian tricolour with the slogan "No to war".
Police began examining Moskalyov's social media activity and he was initially fined 35,000 roubles ($US460) for comments critical of the Russian army. In December, investigators opened another case against him on suspicion of discrediting the armed forces, this time based on a social media post in June.
The banned Russian human rights group Memorial said it considered Moskalyov to be a political prisoner.
Biliyenko visited Masha on Tuesday in the children's home, officially named "Social Rehabilitation Centre For Minors Number 5", and came away with drawings she had made for her father. He was also allowed to photograph a letter she had written him that read "Dad, you are my hero".
Shortly after invading Ukraine last year, Russia outlawed the act of discrediting the armed forces and provided for jail sentences of several years. ($1 = 76.5500 roubles)
