Ringelblum was born in Buczacz, Poland (now Ukraine) in 1900. He earned a doctorate in history at the University of Warsaw in 1927. From a young age, Ringelblum belonged to the Po'alei Zion and was active in public affairs. For a while he taught high school and subsequently commenced working for the Joint Distribution Committee in Poland. In November 1938 the JDC sent him to the border town of Zbaszyn, where 6,000 Jewish refugees from Germany were gathered. These people had been forced out of Germany and not allowed into Poland. Ringelblum spent 5 weeks in Zbaszyn as the person in charge of the refugees and his experiences there had a great impact on him.
After the Germans invaded Poland in September 1939, Ringelblum continued working for the JDC. He ran welfare programs and soup kitchens for the Jews of the Warsaw Ghetto. He instituted House Committees, which attempted to deal with the growing deprivation within the ghetto. Along with his friend Menahem Linder, Ringelblum also founded a society for the advancement of Yiddish culture (Yidishe Kultur Organizatsye) in the ghetto.
In 1923, several Jewish historians in Poland had formed a historical society, with Ringelblum as one of its leaders and prominent scholars. The group was eventually associated with the Institute for Jewish Research (Yidisher Visenshaftlikher Institut, YIVO). Ringelblum was one of the editors of the society's publications, and by 1939, he himself had published 126 scholarly articles. His efforts within that group were just a preview of what he would later accomplish in the Warsaw Ghetto.
Within the first few months of the war, Ringelblum launched his greatest feat: the secret Oneg Shabbat Archive. The name means "Sabbath pleasure," and usually refers to cultural gatherings taking place on Sabbath. Thus, Ringelblum's archive was aptly named because its members met in secret on Saturday afternoons. Initially, the archivists would collect reports and testimonies by Jews who had come to the ghetto to seek help from the self aid organizations.
Ringelblum would collect information during the day, and write notes at night. He knew that what was happening to the Jews was unprecedented, and he was determined to record a complete description of the time and place for future historians. He and his colleagues collected data and wrote articles about towns, villages, the ghetto, and the resistance movement. They also documented the deportation and extermination of Polish Jewry. Near the end of the ghetto's existence, the archivists sent every bit of information they had about the murders, to the Polish underground, which in turn smuggled it out of the country. Thus, Ringelblum helped expose the Nazis' atrocities.
The Oneg Shabbat materials were preserved in three milk cans. One of the sites was uncovered in 1946 and a second in 1950; the other has yet to be located. The archive materials and Ringelblum's own written chronicles constitute the most comprehensive and valuable source of information we have, concerning the Jews in German-occupied Poland and the significance of the events taking place.
In March 1943, Ringelblum and his family escaped the ghetto and went into hiding in the non-Jewish area of Warsaw. During Passover of that year, he returned to the ghetto, which was in the midst of an uprising. He was deported to the Trawniki labor camp, but escaped with the help of a Polish man and Jewish woman. He went back into hiding with his family, however, in March 1944 their hideout was discovered. Soon after, Ringelblum, his family, and the other Jews he had been hiding with were taken to the ruins of the ghetto and murdered.