As one of the most experienced and best equipped Polish divisions, it fought in many of the most notable battles of the Polish-Bolshevik War of 1919 and 1920. Among them was the operation of liberation of Wilno and Battle of Dyneburg in Daugavpils, Latvia (as part of Rydz-Śmigły's Third Army and under his personal command, although the actual commanding officer was Michał Karaszewicz-Tokarzewski). During the Kiev Offensive of spring of 1920, the division formed the core of "Operational Group" and took part in the battle of Zhytomyr (April 25), capturing the city of Kiev itself (May 7). After the Polish withdrawal, the unit took part in heavy retreat battles and shielded the retreat of the rest of the Polish forces. After several clashes with the 1st Cavalry Army, the division broke off and reached the area of the Wieprz River, from where it started the counter-offensive during the Battle of Warsaw (see Battle of Dęblin and Mińsk Mazowiecki). On the second day of the Polish offensive, August 16, the division managed to outflank the Bolshevik Mozyr Group by a forced march of over 56 kilometres. After that the division, commanded by Stefan Dąb-Biernacki, was attached to the Second Army and took part in the second biggest battle of the war, the Battle of the Niemen River. During the battle, the unit formed the core of the "Wilno Group" and took part in a successful outflanking manoeuvre of the Bolshevik forces centered on the city of Grodno.