Fabian Steinheil was born in Estonia and became a lieutenant in the Russian army in 1782. He took part in the war in Finland in 1788 and in 1791 he worked with construction of fortifications in Old Finland.
He became a Major General in 1979 and took part in the campaigns in Prussia in 1805 and Poland in 1807. He became a Lieutenant General in 1807 and commanded the Russian troops on Åland in 1809 during the Finnish War.
In 1810 he was appointed as the Governor-General of Finland. He was well regarded by the Finnish population and was made a count in 1812. He took part in the war agains Napoleon as the commander of a army in Courland and Livonia. He returned to the post of Governor-General which he held to 1924.