Yosef Sprinzak was born in Moscow, Russia but following the expulsion of Jews in 1891 moved with his family to Chisinau where he was a founder of the Tze'rei Zion (Zion Youth). He began medical school at the American University in Beirut in 1908 and settled in Palestine in 1910, during the Second Aliyah (1904-1914). Along with Eliezer Kaplan Sprinzak headed Hapoel Hatzair ("The Young Worker') a Zionist socialist faction formed in 1905 and one of the organisations that consolidated to form Mapai in 1930. Its members were pro-British and supported Chaim Weizmann. He was a founder of the Histadrut in 1920 and acted as secretary general of the organisation from 1945 to 1949. Sprinzak was elected to the position of speaker of the provisional parliament on 15 July 1948, a role in which he helped lay the foundations of Israel's parliamentarism. He was elected to the first Knesset in 1949 as a member of Mapai, and became the Speaker of the new body. He was re-elected and remained speaker in both the second and third Knessets. As part of his role as speaker, Sprinzak became acting President of Israel when Chaim Weizmann fell il from 12 December 1951. After Weizmann's death on 9 November 1952 Sprinzak served as interim President until inauguration of Yitzhak Ben-Zvi on 10 December 1952.