Stefan Czarniecki came from an impoverished family of gentry. All the honours and titles he received, he owed not to his name, but to his personal virtues and the qualities of his character (his saying "I'm not made of land or brine, but of the wounds that are mine" became a national proverb), his personal courage and extraordinary tactical skills. As he had eight siblings, and the family estate was rather small, he joined the renowned Lisowski Riders, a mercenary light cavalry unit organised in the 17th century by Aleksander Lisowski. Serving under the banner of Idzi Kalinowski and already an officer at the tender age of eighteen, he took part in the victorious Battle of Chocim against the Turks (1621).
Czarniecki used the military skills he acquired later, in all the major battles and wars fought by Poland in the period: in 1624 against the Tartars at Martynów; between 1626 and 1629 against the Swedes in Prussia; in 1632 at Smolensk as a lieutenant in a Cossack unit; in 1637 against the Cossacks at Kumejki; and in 1644 routing the army of Tuhai-bey at Ochmatów. In recognition of his services, he finally received an estate at Popowa Góra near Smolensk. In 1648 he was sent as an envoy to the Tartar khan, where he was imprisoned and given up as deceased by the Polish court. However, eventually he returned to his native Czarnica and in 1651 took part in the Battle of Beresteczko, crushing the armies of the rebellious Ukrainian Hetman Bohdan Chmielnicki (Khmyelnitskiy).
Czarniecki's lucky roll was broken in June 1652 during the Battle of Batoh, where he narrowly escaped death. Reportedly hidden in a haystack, he witnessed the massacre of several thousand Poles at the hands of the Tartars. This experience turned a stern soldier into a cruel avenger. Rising through the ranks, he first pacified Ukraine and then resisted the Swedes during their invasion of Poland in 1655 - 1660 (the "Swedish Deluge"). It turned out that his guerilla-type warfare was the only effective measure against the huge firepower and extreme mobility of the Swedish forces. After initial failures, Poland, allied with Denmark, managed to push the Swedes out of the country and out of the Danish territories.
Six weeks before his death, Czarniecki finally received the coveted baton of Grand Crown Hetman, the highest military honour. He died on 16 February 1665 from wounds sustained while quelling a rebellion in Stawiszcz, Ukraine.