In 1838, Ivan Krasnov was elected the director of the board of the Don Cossack Voisko and assistant to the Ataman for civil affairs. In 1841–1842 he served as Cossack field chieftain of Don Cossack Voisko regiments in the Caucasus and wrote the book "Notes on the War in Caucasus" ("Записки о кавказской войне"). In 1843–1848 he commanded the Life Guards of the Cossacks regiment. During Crimean War Krasnov served in the rank of field chieftain (ataman) of Don Cossack Voisko regiments within the Crimean Army, and organized the defense of the city of Taganrog during the Siege of Taganrog in 1855. In 1856 he was appointed general of the 4th military district of Don Voisko.