Cornies was born in the Vistula delta Mennonite settlement of Bärwalde (Niedźwiedzica), near Danzig (Gdańsk) in West Prussia.
In 1804, his family moved to Molotschna, a Mennonite settlement in what is now Ukraine, but then was part of the Russian Empire.
Cornies was the first president of The Agricultural Improvement Society, an Odesa-based commission that supported German colonists.
The organization introduced modern farming practices to the colonies and later extended its reach to education and social life.
Cornies owned a large estate, Jushanlee, a model farm and showplace of south Russia.