Long before his death, he was the last one to stay in the Polish People's Republic despite harassment by the PZPR party authorities.

From the 1970s, he collaborated with the Workers' Defence Committee and other political groups opposing Poland's Communist regime.

[7] When Edelman's mother Cecylia died, he was 14 years old, and was looked after by other staff members at the hospital where she had worked in Warsaw, the city he always called home.

"[9] As a child, Edelman was a member of Sotsyalistishe Kinder Farband (SKIF), the Jewish Labour Bund's youth group for children.

As conditions for Jews worsened in the 1930s, Bund members preferred to challenge the mounting antisemitism rather than flee.

In 1942, as a Bund youth leader he co-founded the underground Jewish Combat Organization (Żydowska Organizacja Bojowa, ŻOB).

[13] When the Germans had stopped their campaign of transporting Ghetto residents to Treblinka extermination camp in September 1942, only 60,000 had remained.

The Jewish Combat Organisation had begun acquiring weapons and organizing into units that would make up for lack of training and munitions with an intimate knowledge of the ghetto, both above ground and in its sewer network.

[9] It was on the second day of the Uprising, while protecting the retreat of Edelman and other comrades, that another prominent insurgent and Bundist, Michał Klepfisz, was killed.

[15] On the morning of May 10, Edelman and his few remaining comrades escaped through the sewers and made their way to the non-Ghetto part of Warsaw to find safety among their Polish compatriots.

[9] After World War II, the Ghetto Uprising was sometimes given as an unusual instance of active Jewish resistance in the face of the horror perpetrated by the Germans.

They had to deal with certain death, stripped naked in a gas chamber or standing at the edge of a mass grave waiting for a bullet in the back of the head....

[16] After the capitulation, Edelman together with a group of other ŻOB fighters, hid out in the ruins of the city as one of the Robinson Crusoes of Warsaw before being rescued and evacuated with the help from the centrist Armia Krajowa (Home Army).

After World War II, he studied at Łódź Medical School and became a noted cardiologist who invented an original life-saving operation.

[16] In 1983, he refused to take part in the official celebrations of the 40th anniversary of the Warsaw Ghetto Uprising sponsored by Poland's Communist government,.

In an open letter dated February 2, 1983, he wrote of his refusal of invitation:Forty years ago we fought not only for our lives.

Hanna Krall, "Shielding the Flame" A couple of days before the official event, on April 17, 1983, several hundred Solidarity members staged a commemoration of their own, gathering spontaneously at the Warsaw Ghetto Memorial.

He supported the 1999 NATO bombing of Yugoslavia as well as the 2003 Iraq war, both of which he saw as instances of American democracy saving countries from fascism again.

[34] In his old age, Edelman spoke in defence of the Palestinian people, as he felt that the Jewish self-defence for which he had fought was in danger of crossing the line into oppression.

[40] Władysław Bartoszewski, former Polish Minister of Foreign Affairs and an Auschwitz survivor, led the tributes to Edelman, saying: "He reached a good age.

"[13][38] Roman Catholic Bishop Tadeusz Pieronek said: "I respect him most for the fact that he stayed in this land, which made him fight so hard for his Jewish and Polish identity.

The documentary Marek Edelman... And There Was Love in the Ghetto, directed by Andrzej Wajda and Jolanta Dylewska, was released in 2019.