Admiral Viktor Sokolov, commander of Russia's Black Sea Fleet based at Sevastopol, was shown at a remote meeting of the country's defence leaders.
It was not clear when the video was filmed but it pushes back on Ukrainian claims that he was killed in last week’s attack on the Crimean headquarters of Russia’s navy.
Video and photographs released by the Russian Defence Ministry show Admiral Sokolov and other fleet commanders apparently joining an in-person meeting led by Defence Minister Sergey Shoigu.
A Defence Ministry statement said the meeting had been held earlier in the day but did not name Admiral Sokolov.
He appeared on screen several times in an eight-minute video released by the ministry but was not shown speaking.
Ukraine's special forces said on Monday that the admiral had been killed alongside 33 officers in a missile attack in Sevastopol last week.
The Kremlin had told reporters moments before the ministry's statement was released that it had “no information” regarding the status of the commander and deferred questions to the Defence Ministry.
After the video was aired, Ukraine's Special Operation Forces said on Telegram: “Since the Russians were urgently forced to publish a response with Sokolov allegedly alive, our units are clarifying the information.”
The Crimean Peninsula, which Moscow annexed from Ukraine in 2014, has been a target for attacks since Russian President Vladimir Putin ordered a full-scale invasion of its neighbour 20 months ago.
On Monday, the Russian-installed governor of Sevastopol, Mikhail Razvozhayev, said Russian air defences had shot down a missile near a military airfield in Belbek, a village close to the port city. He gave no details about damage or casualties.
Kyiv has launched an increasing number of attacks on naval sites in Crimea in recent weeks as the brunt of its summer counter-offensive progresses slowly in the east and south of Ukraine, the Institute for the Study of War said.
Friday’s attack was followed by another strike on Saturday.
Admiral Sokolov was not named in a statement by the Special Operation Forces, but Anton Gerashchenko, an adviser to Ukraine's Minister of Internal Affairs, posted his name and a photo on social media.
Ukraine’s military said the air force conducted 12 strikes on the Black Sea Fleet headquarters, hitting areas where there were personnel, military equipment and weapons.
Two anti-aircraft missile systems and four Russian artillery units were hit, the military said.
The casualty figures were announced as Russian drone and missile strikes near Odesa killed two people and damaged an abandoned hotel and a grain silo in the Black Sea port city. Russian attacks elsewhere were blamed for killing six other civilians in the past day in Ukraine.
Ukraine’s air force reported that it shot down all Russian drones launched overnight, but one of 12 Kalibr missiles and two P-800 Oniks cruise missiles apparently made it through.
Russia has repeatedly hit port and grain storage sites in Odesa since pulling out of a deal that allowed Ukraine to export grain to countries facing the threat of hunger. The attacks have destroyed silos, warehouses, oil terminals and other infrastructure critical for storage and shipping.
The Russian Defence Ministry said long-range missiles and drones were used to strike sites that it alleged housed foreign mercenaries and trained saboteurs.
The ministry did not name the locations or provide other specifics to support its claim. It also said it shot down several Ukrainian drones.