Born in Zułów (now 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 (Russia, Germany and Austria-Hungary) 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 Austro-Hungarian and German troops against Russia. He hoped that Russia will be defeated by the Central Powers and that the polish lands will become unified for the firs time since the Partitions.
As the end of the war was nearing and the victory of the Entente became apparent, Pilsudski organized a mutiny in which his troops declined to swear allegiance to the Austrian emperor in 1917. As a result of this action Pilsudski was arrested and sent to Magdeburg stronghold while his men were either interned or forced to join Austro-Hungarian army.
With the Treaty of Brest-Litovsk Russia had to renounce claims to what was until then its' part of Poland, and Germany and Austria-Hungary announced the setting up of a Kingdom of Poland.
In 1918 Pilsudski was released by the revolted german troops and on November 11 he became the provisional head of the newly-formed Polish state. However, it was Pilsudski's political opponent, Roman Dmowski, who represented Poland at the Versailles Treaty .
With the outbreak of hostilities in February 1919, the Polish-Soviet war started, however both sides of the conflict committed minor forces. Pilsudski did not want to start the offensive against bolshevik Russia, as he did not want to help anti-communist forces who did not support the independence of Poland.
In April 1920, Pilsudski signed the alliance with Ukraine under leadership of Semen Petlura, where Poland passed to Ukraine its rights to the right bank of Dnipro river up to the 1772 border, in exchange for cession of Galicia and Volhynia to Poland. Subsequently the Polish army under Pilsudski leadership attacked succesfully the Russian army in the Ukraine, pushing back the Red Army and occupying Kiev. However, his plan to destroy the enemy units stationed in the area and disrupting the bolshevik mobilization in the Byelorussia failed.
The Soviets counter-attacked, recapturing the Ukraine and advancing through Poland. Thanks to Pilsudski's brilliant command, the overwhelming bolshevik forces were defeated in the Battle of Warsaw (known to Poles as the Miracle on the Vistula River).
The final Treaty of Riga (1921) forced by Pilsudski's political oponents gave the Belorussia with Minsk to Russia, that together with incorporation of Central Lithuania after referendum of 1922, made Poland more like national state, in opposition to Pilsudski aim of restoring Polish-Lithuanian Commonwealth as a federal country including all Central European nations.
The newly-passed constitution of March 1921 cancelled both posts Pilsudski occupied (Commander of the State and Commander in Chief). In December 1923 Pilsudski has been elected president of Poland by the polish sejm, but he declined. He remained the military leader until 1923. After a three-year retirement he returned to stage a successful military coup d'etat in May 1926. Pilsudski started the Sanacja movement, or movement for sanitization of the political and social life. Although he played an overwhelming role in Poland, he never took any political posts apart from the Commander of the State.
Pilsudski's death in 1935 left a political vacuum, many unresolved problems for the newly re-established Polish state, and started a short period of struggle for power between various of his former brothers in arms.