Sometimes we see photos of coins or stamps or currency of British Mandate Palestine being reproduced as "proof" that there was a Palestinian state.
If that is true, and British Mandate Palestine is proof of a Palestinian state, then its first leader was - a Jew!
Herbert Samuel was appointed to the position of High Commissioner of Palestine in 1920.
So if the money and stamps supposedly prove that Palestine existed as an independent entity, then even so the first leader of the Palestinian people after the Ottoman era was Jewish.