As the Polish–Swedish war ended, in 1630, Czarniecki enlisted in the Habsburg forces and continued to fight against the Swedes, participating in the battle of Breitenfeld. In 1633 he joined the Commonwealth forces again, to fight under the new Polish king, Władysław IV, in the Smolensk War against Muscovy that lasted until 1634. During the Smolensk War he learned Western tactics used by the foreign mercenary troops. In December 1633 he commanded a raiding unit that successfully raided and pillaged behind the Russian lines, spreading terror, disrupting supply lines, and burning down the town of Kozelsk. For his achievements in that war, in which he advanced to a porucznik rank in the light "cossack" cavalry unit under hetman Marcin Kazanowski, he received some land in the Smolensk Voivodeship near Starodub.