Rabbi Chaim Messas was born in Meknes, Morocco, on 8 Elul 5603 (September 3, 1843), to Rabbi Zechri and his wife Mira. He belonged to the Messas family, one of the most important in Morocco, which produced many sages and rabbinic judges. His older brother, Rabbi Shalom Messas the Elder, was also a scholar, and Rabbi Chaim would present his halachic insights before him.

He was accustomed to study until midday wearing the tefillin of Rabbeinu Tam, and he devoted himself to Talmudic tractates rarely studied in the yeshivot. From his youth, Hevrat Pinto relates, a pure fear of G-d burned in him and his prayers were answered. He was devoted to acts of kindness and bought cooking and baking utensils to lend to the poor. In 5635 (1875) he became the permanent prayer leader of the synagogue of the Maharchat, and after the passing of Rabbi Shmuel Amar in 5650 (1890) he was appointed a judge on the rabbinical court of Rabbi Yaakov Berdugo, author of Edut BeYaakov. As a judge he sought first to bring the parties to a compromise.

As head of his yeshiva he raised close to one hundred and fifty students who became the spiritual leaders of Meknes, among them Rabbi Chaim Berdugo, Rabbi Yosef Elkoubi, Rabbi Raphael Baruch Toledano and his own son, Rabbi Yosef Messas, later Chief Rabbi of Haifa. Twice he planned to move to the Land of Israel, in 5646 and again in 5660, but the death of his brother, and later of his friend Rabbi Shalom Amar, prevented it.

Works: Nishmat Chaim, sermons and insights on Tanach, and Leket HaKemach, a collection of laws arranged alphabetically. His writings were published through the efforts of his son Rabbi Yosef, who noted that many of them had decayed or been lost.

His disciple Rabbi Raphael Baruch Toledano recounts that in Nissan 5663 (1903), when the Jewish community of Meknes was attacked, Rabbi Chaim threw himself to the ground amid the crowd, calling everyone to repentance and leading the whole assembly in reciting Shema Yisrael, until the attackers fled. He fell ill shortly afterwards and never recovered. He passed away on 8 Tammuz 5664 (June 21, 1904) and was buried in Meknes. His students Rabbi Yosef Berdugo and Rabbi Yehoshua Adrai composed laments in his memory, and his son founded the Nishmat Chaim synagogue in Haifa, named after him.