[11][12] Under the influence of Chaim Weizmann, whose family had immigrated from Belarus to Manchester, Simon belonged to the first generation of leading British Jews who preferred Zionism to conventional religiosity and who pressed for Hebrew to supplant Yiddish as the main language of the diaspora.

[4] Simon came under the influence of Ahad Ha'am (Asher Zvi Hirsch Ginsberg), a leading figure of cultural Zionism, and went on to translate many of his works into English[13] as well as writing his biography.

[16] The draft of the declaration noted down by Simon read: "H(is) M(ajesty's) G(overnment) accepts the principle that P(alestine) should be reconstituted as the Nat(ional) Home of the J(ewish) P(eople).

"[16] Simon accompanied Weizmann as a member of the Zionist Commission alongside Israel Sieff, M. D. Eder and others in 1918 to begin talks with the government of David Lloyd George on the establishment of a Jewish State in Palestine.

From 1946 to 1953 Simon lived in Jerusalem where he served as Chair of the Executive Council of the Hebrew University and from 1949-50 as its President, preceded by Judah Leon Magnes and followed by Selig Brodetsky (1949-1952).