Carl Johan Adlercreutz (27 April 1757 – 21 August 1815) was a Swedish general and statesman, born in Borgå (Porvoo), Finland on family estates. Entering the Swedish army aged 13 in the Finnish Light Cavalry Brigade, he was present when Gustav III launched his coup-d’état. He studied military theory in Stockholm.
In 1777 he joined the guarding the Finnish border against Russian aggression. Adlercreutz first saw action in the 1788–1790 Russo-Swedish War, where he distinguished himself. He was promoted Major in 1791 and Squadron Commander 1792. During the Anjala conspiracy he not only remained faithful to the King but actively refused to join the conspirators, subsequently taking part in the trials against them.. He was thereafter appointed the commanding officer of the Nyland Dragoons, holding this post until 1804, when he was made Ofverste (Colonel-in-Chief) of the newly raised .
His rise through the ranks was remarkable for the era. Advancement at this time depended heavily on powerful patrons and connections at court — something Adlercreutz largely lacked, despite being brother-in-law to Colonel Johan Adam Cronstedt and having married into the Swedish high nobility. His career advancement was therefore essentially his own achievement.