He was descended from a long line of Masoretes, starting with someone called Asher, but nothing is known about them other than their names. His father, Moses ben Asher, is credited with writing the Cairo Codex of the Prophets (895CE); if authentic, it is among the oldest manuscripts containing a large proportion of the Hebrew Bible. Aaron ben Asher himself added vowelization and cantillation notes, and mesorah to the Aleppo Codex, correcting its letter-text according to the masorah.
Maimonides, by accepting the views of Ben-Asher (though only in regard to open and closed sections), helped establish and spread his authority. Referring to a Bible manuscript then in Egypt, he wrote: "All relied on it, since it was corrected by Ben-Asher and was worked on and analyzed by him for many years, and was proofread many times in accordance with the masorah, and I based myself on this manuscript in the Sefer Torah that I wrote". More recently, Umberto Cassuto used this manuscript as the basis of his edition of the Hebrew Bible.
Aaron ben Moses ben Asher was the first to take Hebrew grammar seriously. He was the first systematic Hebrew grammarian. His Sefer Dikdukei ha-Te'amim (Grammar of the Vocalizations) was an original collection of grammatical rules and masoretic information. Grammatical principles were not at that time considered worthy of independent study. The value of this work is that the grammatical rules presented by Ben-Asher reveal the linguistic background of vocalization for the first time. He had a tremendous influence on the world of Biblical grammar and scholarship.
A rival system of note was that developed by the school of Ben Naphtali.
In his critiques of Karaites, Saadia Gaon mentioned a "Ben-Asher." Until recently, it never occurred to scholars to associate the "Ben-Asher" of Saadia's diatribe with the famous Aaron ben Asher of Tiberias. Recent research indicates, however, that it is probable that the subject of Saadia's attack was Aaron ben Moshe ben Asher.
Documents found in the Cairo Geniza also indicate that ben Asher was a Karaite.