Since 1979 he has been the director of the Russian (former Soviet) Deepwater Submersibles Laboratory. He received a Doctor of Sciences degree in 1985. Sagalevich took part in the construction of Pisces VIII, Pisces IX and MIRDeep Submergence Vehicles (DSV) and completed more than 300 submersions as the chief pilot of DSVs. Between 1989 and 2005 he led 28 expeditions on MIR DSV. He was the pilot of MIR during expeditions to the British passenger liner RMS Titanic, the German battleship Bismarck, the Soviet submarine K-278 Komsomolets, the Japanese submarine I-52,[2] and the Russian submarine K-141 Kursk.
Sagalevich holds the world record for the deepest fresh water dive, at 1,637 meters (5,371 ft) (in Lake Baikal aboard a Pisces in 1990).[3]
On 2 August 2007 Sagalevich was the pilot of MIR-1 DSV, which reached the seabed at the North Pole during the Arktika 2007 expedition.
Hero of the Russian Federation (9 January 2008), "for courage and heroism displayed in extreme conditions, and the success of high-latitude Arctic deep-sea expedition."