Rabbi Ḥayim Naḥum was born in 1872 in Izmir, Turkey. He was an extraordinarily intelligent person with an exceptionally diverse education. He received his formal Jewish education in Tiberias and his secondary education at a French Lycee. He held a degree in Islamic Law from Constantinople. He attended the Sorbonne's School of Oriental Languages in France while at the same time attending the Rabbinical Academy of Paris. He then returned to Constantinople and taught at the Turkish Military Academy.
Rabbi Naḥum's unusual background and eclectic interests earned him great respect. From 1909 until 1923, he served as Ḥakham Bashi (Chief Rabbi) of the Ottoman Empire and was granted the title of "Effendi" (Lord) by the Turkish government. Rabbi Naḥum successfully intervened in favor of Jews in various localities of the Empire, especially in assuring government protection for them during World War I (it seems that it was due to him that the project of expelling the Jews from Jerusalem was averted).
In 1923, Rabbi Naḥum agreed to become the head of the Jewish community in Cairo, and thus the Chief Rabbi of Egypt. Here, too, Rabbi Naḥum became a man of noted success within the greater gentile society. From 1930 to 1934 he was a member of the Egyptian Parliament. He helped found the Royal Academy of the Arabic Language, and was instrumental in making possible the reconvening the Society for the Historical Study of the Jews of Egypt.
With the rise in Arab nationalism in the late 1940s, life for Egyptian Jews became increasingly difficult. There was an abundance of political intimidation and economic oppression. Although he gave into government pressure to denounce Zionism (using vague, meaningless phrases), he held firm in his refusal to have synagogues recite prayers for an Egyptian victory in the 1948 war. Ignoring his own failing health (and blindness), Rabbi Naḥum spent his final years in service to the greatly diminished Egyptian Jewish community. He was 88 years old when he died.