Gruzinov was born to a family of a Russian orthodox priest. He received Christian education, then studied at Imperial Moscow University and Saint Petersburg Academy of Physicians and Surgeons followed by studies in Western Europe. He worked as adjunct professor of anatomy (from 1809) and professor of anatomy and physiology (from 1811) at the Medical Department of Moscow University. After Napoleon's invasion of Russia in 1812 he began to help wounded soldiers in the Russian Army.