Rabbi Masoud Raphael Elfassy was born around 1680 in Fez, Morocco, the son of Rabbi Raphael. He studied under the sages of his city, of whom he became one, and appears to have studied for a time in Algiers. He married Miriam of the Assor family.

In 1723 he decided to go up to the Land of Israel. Tradition relates that he set out with his faithful servant in a merchants' caravan, and that the two kept learning despite the hardships of the road. Passing through Tunis, he chose to settle there. He founded a synagogue and Talmud Torah, the Tslat Elfassy, and served as a dayan. In 1773, on the death of Rabbi David Najar, he was appointed av beit din and chief rabbi of Tunis.

Renowned for his responsa, he corresponded with the sages of Algiers. With his sons Rabbi Shlomo and Rabbi Chaim, he wrote Mishcha DeRabuta, notes on all four sections of the Shulchan Aruch (Livorno, 1805). Among his rulings: where the Talmud contradicts the Zohar, the Talmud is followed.

He passed away in Tunis on the night after Shabbat, 1 Tevet 5535 (1774). His son Rabbi Shlomo succeeded him as av beit din, and the communities of Tunis still recall his soul in the memorial prayer on the night of Yom Kippur.