Nahum Sokolow was born in Wyszogrod, Russian Poland in 1859 and received a traditional Jewish education. In secular subjects he was an autodidact specializing in languages and literature. He spoke German, French, Spanish and Italian as well as English, Yiddish, Hebrew, Polish and Russian. By profession he was a journalist writing for the Warsaw periodical HaTzefira. In time he became the owner and editor of the periodical. He wrote a number of books, one on Hebrew geography, another on anti-Semitism. In 1901 he wrote a tract in which he attempted to convince religious Jews that despite the secular leadership of the Zionist movement, there was no ideological reason for them to oppose the cause. Sokolow later translated Herzl's Altneuland into Hebrew giving it the title Tel-Aviv. In 1918 he wrote one of the earliest accounts of the history of Zionism controversially beginning his study in the mid-seventeenth century.
Sokolow was not a member of the Hovevei Zion movement even though his HaTzefira was Zionist in orientation. Indeed when Herzl's "The Jewish State" was published, Sokolow dismissed the Eretz-Israel option as an illusion. However, Sokolow went through a metamorphosis and rallied to the Zionist organization in particular after David Wolffsohn, Herzl's successor called on him to become the Secretary General of the World Zionist Organization. Sokolow held this position from 1907-1909 but differences over the political nature of Wolffsohn's Zionism led to a rift between the two men. In 1911, under a new administration, Sokolow became responsible for the political portfolio and tried to win support for the Zionist idea in particular in the United States and in Britain. Just before the outbreak of the First World War he had visited various Arab leaders but with the outbreak of hostilities he moved to England where he worked closely with Chaim Weizmann.
Sokolow became a key figure in the negotiations for the Balfour Declaration when he met with French officials and won a pro-Zionist statement from them in May 1917. He was received by Cardinal Gasparri, the Papal Secretary of State, who assured Sokolow that Zionism need not fear the Vatican. These missions elevated his status in the movement as evidenced by the fact that at the Paris Peace Conference in 1919 he headed the Zionist delegation. In 1921, Sokolow was elected Chairperson of the Zionist Executive during which time he traveled extensively, putting the case of the movement before various dignitaries including Mussolini. In 1931 following Weizmann's departure from the Presidency of the World Zionist Organization, Sokolow assumed his mantle although he continued the policies of his predecessor. When in 1935 Weizmann returned to the Presidency, Sokolow was elected honorary President and assumed responsibilities in the newly formed Cultural Department. He died in 1936. His remains were reinterred at Mt. Herzl, Jerusalem in 1956.