During the Kościuszko Uprising of 1794 Jasiński was among the most prominent members of the radical wing of the Polish Jacobins and at the same time a successful military commander of partisan forces in the area of the Grand Duchy of Lithuania. In April of that year he liberated the city of Vilnius by leading a successful uprising there. Supported by Tadeusz Kościuszko and appointed the commander in chief of all the partisan forces in the former Grand Duchy, he managed to defeat numerous Russian garrisons in the area. However, accusations of radical republicanism brought him into conflict with the state authorities, and by the beginning of June he was forced to resign as commander-in-chief of Lithuanian forces and pass his office to General Michał Wielhorski. Jakub Jasiński continued to harass enemy forces in Lithuania and then withdrew with a small partisan troop towards Warsaw. There he perished in November during the defense of Warsaw against the forces of Alexander Suvorov.