Born in Zulow (Lithuania) into a patriotic, artistocratic Polish family and brought up in austere circumstances, he attended a grammar school in Vilnius. He studied at the University of Kharkov and then joined a clandestine revolutionary and anti-tsarist organization "The People's Will". In 1887 the Tsarist authorities arrested him and sentenced him to exile in Siberia for five years. His brother, Bronislaw Pilsudski, also participated in a revolutionary plot, and became an associate of Lenin's brother.
After his release encountered the socialist movement and in 1892 he founded PPS, The Polish Socialist Party. In 1900 he was arrested again for editing an underground leftist daily Robotnik ("The Worker"). He managed to escape and organized military groups of the party. At that time he believed in revolutionary guerilla warfare and carried out bank and train raids. With the money he seized he slowly built up a new revolutionary army with the goal of gaining independence from Russia.
In the years immediately before World War I Pilsudski became a leading figure who linked and helped several military, paramilitary or guerilla groups. All those groups aimed at Polish independence from the European powers (and particularly Russia?) which had dominated the region since the late 18th Century (see History of Poland).
In 1914 he establised the Polish Legion (the predecessor of the Polish Army) and fought alongside Austrian and German troops against Russia. However, he was unwilling to take orders from the German and Austro-Hungarian Command and was arrested. With the Treaty of Brest-Litovsk Russia had to renounce claims to what was until then Polish-Russia, and Germany and Austria announced the setting up of a Kingdom of Poland.
In 1918 Pilsudski was released and on November 11 he became the provisional head of the newly-formed Polish state. However, at the Versailles Treaty Pilsudski's political opponent Roman Dmowski represented Poland.
In 1920, the Polish army under Pilsudski invaded the Soviet Ukraine, pushing back the Red Army and occupying Kiev. Pilsudski claimed that he had made a pre-emptive strike against Bolshevik expansionism. The Soviets counter-attacked, recapturing the Ukraine and advancing through Poland, until their defeat at the Battle of Warsaw (known to Poles as the Miracle on the Vistula). Pilsudski won considerable gains for Poland in the Treaty of Riga (1921).
He remained the military leader until 1923. After a three-year retirement (?) he returned to stage a military coup in 1926. Later he played an overwhelming role in Polish political life and some forms were suppressed.
Pilsudski's death in 1935 left a political vacuum and many unresolved problems for the newly re-established Polish state.