He was the great-grandson of R. Chaim Abraham Gagin, the first Hakham Bashi of the Holy Land during the Ottoman Empire, and the son and nephew respectively of Rabbis Isaac and Abraham Gaguin. He was the great-great grandson of the famous scholar and kabbalist, Sar Shalom Sharabi.
He studied at the "Doresh Zion" College, Jerusalem and was a pupil of R. Jacob Alfiya.
At an early age, he contributed articles to the Palestinian Hebrew Press ("Hahhabbezeleth" et al) on aspects of Jewish traditional observances, as well as on biblical and philological matters. He was awarded rabbinical diplomas by numerous authorities, including R. Haim Berlin and Chief Rabbis Jacob Meir, C.B.E. and Abraham Kook, C.B.E. of Palestine. In 1911, Rabbi Gaguine was appointed to serve in the office of dayyanut in Cairo.
In 1919, he was invited to serve In Manchester, being appointed Ab Beth Din 1n 1920.
In 1927 he was appointed Rosh Yeshibah of Judith Montefiore College in Ramsgate. Dayan of the Beth Din of the autonomous Jewish Community of Egypt from 1911 to 1919.
Senior Rabbi of the Sephardi Congregation of Withington, Manchester, 1919-1926. Dayan of the Manchester Beth Din, 1920-1926.
Appointed Ecclesiastical Chief (Haham) and Ab Beth Din of the Spanish and Portuguese Jews in England in 1920.
Principal (Rosh Yeshivah) of the Judith Montefiore Theological College, Ramsgate, from 1927. Appointed by Acting of Parliament in 1934 as Vice President of the Rabbinical Commission for the Licensing of Shochatim in Great Britain. Head of the Sephardi Medrash "Heshaim" in London from 1935.
