Born in 1933, Petrov lived through the Second World War and the Axis invasion of the Soviet Union. Working at first as a shepherd, and training at a teaching college, he was eventually called up for military service, and studied at the A. A. Zhdanov Naval Political School. He then entered the navy's Northern Fleet, where he would spend most of his career. Petrov at first served aboard destroyers in the surface fleet as officer for the Komsomol organization, and after further studies joined the submarine branch as a deputy commander for political affairs on several of the Northern Fleet's submarines. By the late 1960s he had risen to serve as political officer in staff positions and by the late 1970s he was deputy head of the navy's Political Directorate.