The turning point in Luzzatto's life came at the age of twenty, when he made the claim that he was receiving direct instruction from a mystical being known as the maggid. While such stories were not unknown in kabbalistic circles, it was unheard of for someone of such a young age. His peers were enthralled by his written accounts of these "Divine lessons," but the leading Italian rabbinical authorities were highly skeptical and threatened to excommunicate him. Just one hundred years earlier another young mystic, Shabbetai Zevi (d.1676), had rocked the Jewish world by claiming to be the Messiah. Although, at one point, Zevi had convinced almost all European and Middle Eastern rabbis of his claim, the episode ended with him recanting and converting to Islam becoming an apostate to Judaism. The global Jewish community was still reeling from that, and the similarities between Luzzatto's writings and Zevi's were perceived as being especially dangerous.
These writings, only some of which have survived, describe Luzzato's belief that he and his followers were key figures in a messianic drama that was about to take place. He identified one of his followers as the Messiah son of David, but assumed for himself the role of Moses, claiming that he was that biblical figure's reincarnation. According to his writings, Moses was ranked higher than the Messiah and was the real catalyst for the Redemption. Furthermore, he described all of his corporeal actions as a playing out of the redemptive process: his wedding and the consumption of his marriage, for example, were explained as representing the necessary union of the male and female aspects of the mystical Judaic notion of the Godhead.
Threatened with excommunication, Luzzatto finally swore not to write the maggid's lessons or teach mysticism. In 1735, Luzzatto left Italy for Amsterdam, believing that in the more liberal environment there, he would be able to pursue his mystical interests. Passing through Germany, he appealed to the local rabbinical authorities to protect him from the threats of the Italian rabbis. They refused and forced him to sign a document stating that all the teachings of the maggid were false. Most of his writings were burned, though some did survive.
When Luzzatto finally reached Amsterdam, he was able to pursue his studies of the kabbalah relatively unhindered. Earning a living as a diamond cutter,he continued writing but refused to teach. It was in this period that he wrote his magnum opus the Mesillat Yesharim (1740), essentially an ethical treatise but with certain mystical underpinnings. The book presents a step-by-step process by which every person can overcome the inclination to sin and reach a level of prophecy. Couched in rabbinic language very distinct from his other writing, it may have been written as a means of winning legitimacy among the local Jewish community. Another prominent work, Derekh Hashem (The Way of God) is a philosophical text about God's purpose in Creation, justice, and ethics.
One major rabbinic contemporary who praised Luzzatto's writing was Rabbi Eliyahu of Vilna,the Vilna Gaon (1720 - 1797),who was considered to be the most authoritative Torah sage of the modern era as well as a great kabbalist himself.He was reputed to have said after reading the Mesillat Yesharim, that were Luzzatto still alive ,that he would have walked from Vilna to learn at Luzzatto's feet.He stated that having read the work,that there was nothing superfluous in it. This is considered to be one of the highest praises that one sage can grant another.
Luzzatto also wrote poetry and drama, most of it secular (though many scholars have identified mystical undertones in this body of work as well). His writing is strongly influenced by the Jewish poets of Spain and by contemporary Italian authors.
Frustrated by his inability to teach kabbalah, Luzzatto left Amsterdam for the Holy Land in 1743, settling in Acre. Three years later, he and his family died in a plague. It was only a century later that Luzzato was rediscovered by the Mussar Movement, which adopted his ethical works. It was the great Torah ethicist, Rabbi Yisrael Salanter (1810 - 1883) who placed the Messilat Yesharim at the heart of the Mussar (ethics) curriculum of the major Yeshivot of Eastern Europe.
The Hebrew writers of the Haskala,the Jewish expression of the Enlightenment, adopted his secular writings and deemed him the founder of modern Hebrew literature. He is buried near the Talmudic sage Rabbi Akiva in Tiberias, northern Israel.