The origins of the Piłsudski Institute date back to March 1923, when colleagues and supporters of Józef Piłsudski (led by Col. Walery Sławek, Aleksander Dębski, Aleksander Prystor, Wacław Sieroszewski, Adam Skwarczyński, Michal Sokolnicki, Artur Śliwinski, Kazimierz Świtalski, Leon Wasilewski) collaborated on establishing the Institute for Research into the Modern Polish History (Instytut Badan Najnowszej Historii Polskiej).
To this end, on November 15, 1924, Col. Walery Sławek requested all Piłsudski "legionnaires" to protect and donate documents, memoirs, prints, appeals, proclamations, photographs, letters and hand-written notes from their time in service.
Sławek's appeal made it clear that all records were deemed valuable in demonstrating legionnaires’ individual contributions and the broader challenges posed by opposition from foreign governments and within their own society.
Coverage was devoted to recording all efforts and movements leading to Poland's independence, from the failed January 1863 Uprising to the restoration of the Polish state after World War I.
With support from Marchall Smigły-Rydz (the new commander-in-chief of the Polish forces) and Gen. Tadeusz Kasprzycki, the Institute relocated to larger, new premises adjoining the army headquarters on Aleje Ujazdowskie in Warsaw.
Between 1929 and 1939, several prominent members of the institute (Hipolit Śliwinski, Teodor Furgalski, Boguslaw Miedzinski, Roman Górecki and Wacław Jędrzejewicz) were instrumental in securing crucial historical records and documentation.