Born in Moscow in a family of intellectuals, Zionists of long date, he settled in Warsaw in 1925. After taking refuge in Vilnius during the War, he returned to Warsaw in 1940, and immediately joined the Resistance, which he helped organize. He was interested in young peoples' reactions in the Ghetto, and was responsible for the underground publications of Hashomer Hatzair, of which he was a founding member and leader. Breslaw also was one of the founding members of the JFO.
With Anielewicz, he published a daily bulletin containing information from Radio London and Moscow. He fell on 3 September 1942, aged 22, while trying to help Josef Kaplan.
