In the Finnish War against Sweden, Kulnev led Buxhoevden's vanguard. For his part in the storm of Jakobstad he was awarded a golden sabre. He encouraged guerrilla fighting and fought with distinction at Lapua, Kuortane, Oravais — three engagements which earned him Order of Saint George and the rank of Major General. Denis Davydov, who fought under his command in Finland, described Kulnev's exploits in his memoirs.