The son of a peasant, Kozlov was born and raised in Vladykino, a small village in the Saratov Governorate of the Russian Empire. In 1898 his family emigrated to Petersburg, where Vasily studied in Company's of encouragement of painters' school. After graduating from school, Kozlov was working in studios as master of stucco moulding for building's facades for six years. In 1906-1912 he was a student of the Imperial Academy of Arts. While in school he made friends with Leopold Dietrich, who became a frequent collaborator.
In 1919 Kozlov became a chairman of the Sculptors' committee and later a professor of sculptural faculty at the Academy of Art. He died in 1940, and was buried in the Volkovo Cemetery.
