From 1935 to October 1943, she worked for the Department of Social Welfare and Public Health of the City of Warsaw.
She also pursued informal, and during the war conspiratorial activities, such as rescuing Jews, primarily as part of the network of workers and volunteers from that department, mostly women.
Sendler participated, with dozens of others, in smuggling Jewish children out of the Warsaw Ghetto and then providing them with false identity documents and shelter with willing Polish families or in orphanages and other care facilities, including Catholic nun convents, saving those children from the Holocaust.The German occupiers suspected Sendler's involvement in the Polish Underground and in October 1943 she was arrested by the Gestapo, but she managed to hide the list of the names and locations of the rescued Jewish children, preventing this information from falling into the hands of the Gestapo.
Withstanding torture and imprisonment, Sendler never revealed anything about her work or the location of the saved children.
She was sentenced to death but narrowly escaped on the day of her scheduled execution, after Zegota bribed German officials to obtain her release.
In post-war communist Poland, Sendler continued her social activism but also pursued a government career.
In 1965, she was recognised by the State of Israel as Righteous Among the Nations.
Among the many decorations Sendler received were the Gold Cross of Merit granted her in 1946 for the saving of Jews and the Order of the White Eagle, Poland's highest honour, awarded late in Sendler's life for her wartime humanitarian efforts.
Author: Unknown Source: Teresa Prekerowa "Konspiracyjna Rada Pomocy Zydom w Warszawie 1942-1945"( The underground Council to Aid Jews in Warsaw 1942-1945) Warszawa 1982 ISBN 83-06-00622-4. Immediate source: Irena Sendler 1943 (2) online. License: PD Polish