The information regarding the short life of his son Henio, who became an icon of the Holocaust in Poland, became known to the public from his father's letters.

His father, Ephraim (1873–1941), who was born in the little town of Medzhybizh (Polish: Międzybóż) in Podolia (now in Ukraine) was a member of Hovevei Zion, a follower of the Mizrachi movement,[1] one of the Yavne School founders in Lublin[2] and an active member in a "benefit society" charity fund in Lublin.

Shmuel's mother, Chaya Devora (née Melamed) (1882–1942), was born in Riga (now the capital of Latvia, but then in Imperial Russia).

Zytomirski had taught his students the best works of art of the modern Hebrew poets and writers (Constitution Generation): Bialik, Tchernichovsky, Peretz and Frug.

In his students' hearts he implanted the Zionist vision and the desire for leaving diaspora and aiding the national renewal of the Jews in the Land of Israel.

While teaching he used various advanced pedagogical methods: plays, poetry, public declamation of pieces, and trips out-of-town.

Thanks to the efforts of the Zionist parties, several rooms at the community house on 41 Krawiecka street were renovated and given to the Hakhshara Kibbutzim.

Famous people came to Lublin and lectured in the league's meetings: Zalman Shazar (Rubashov), the author Nathan Bistritzky (Agmon) and Eliyahu Dobkin.

[10] In the early 1930s Shmuel Zytomirski was married to Sara Oksman, who ran a retail store selling stationery.

Over the window of the Zytomirski family store, Anti-Semitic Poles had engraved the word ZYD (in Polish: "Żyd").

In 1937, Shmuel Zytomirski wrote in a letter to his young brother Yehuda, who had immigrated to Mandatory Palestine in that year: and I am very bothered by the question: What will be with my son when he grows up?

On 1 September 1939, the opening day of school, Nazi Germany invaded Poland and World War II began.

Zytomirski, a teacher by profession and Chairman of the Poale Zion movement in Lublin, was appointed by the Judenrat to be the manager of the post office at 2nd Kowalska Street.

This role allowed him, apparently, to make contact with the Polish underground (which delivered him forbidden information and news[11]); to correspond with his young brother, Yehuda (Leon) Zytomirski, who had already immigrated to Mandatory Palestine in 1937; to be in contact with Yitzhak Zuckerman and Zivia Lubetkin[12] from the Jewish resistance in the Warsaw Ghetto and with Hashomer Hatzair members in Vilnius; and to correspond with Nathan Schwalb,[13] Director of the Jewish Agency offices and the HeHalutz movement in Geneva, who was providing assistance to hundreds of youth movement activists in the Nazi-occupied territories.

If collecting clothes for the Germans on the front is needed, it means they are in big trouble...Being a person who had seen matters from a historical perspective, Zytomirski wrote a diary since the beginning of the Nazi occupation.

On 16 March 1942, the transports in freight trains from Lublin District to extermination camps began as part of "Operation Reinhard".

Zytomirski and his son Henio survived the selections of spring 1942, apparently thanks to a work permit (in German: J-Ausweis) that Shmuel had.

On 22 April, the SS held another selection: about 2,500 to 3,000 people without work permits were taken initially to Majdanek and from there to Krepiec (Krępiec) forest which is about 15 km from Lublin.

From the Majdan Tatarski ghetto Zytomirski sent (via the Red Cross organization) a message to his brother Yehuda in Mandatory Palestine: - - - Henio is with me.

On 23 July 1942 Zytomirski sent a letter from the Majdan Tatarski ghetto to Nathan Schwalb in Geneva: You must know how sad and lonely I am.

These words of Zytomirski, "in my solitude I hang all my hopes in you", were used by the Holocaust researcher, Prof. Avraham Milgram, as the title of his article about sending the food packages from Portugal to Jews who were in territories under Nazi occupation.

On 3 November 1943, the massive extermination of all remaining Jewish captives and prisoners in Majdanek and the other camps in Lublin District took place.