Why was St. Jerome named a doctor of the church?

St. Jerome was designated a Doctor of the Church because his writings and teachings are considered to be of particular importance to Roman Catholic theology. This title is reserved for saints whose doctrinal works possess special authority and are regarded as both true and timeless.123

Jerome is traditionally celebrated as the most learned of the Latin Fathers, possessing extensive knowledge of the Bible, the classics, and Christian tradition. His profound influence on the early Middle Ages stems largely from his biblical, theological, ascetical, and monastic works. Most notably, he produced the Vulgate, a Latin translation of the Bible that became the standard version throughout Western Christendom for centuries. Due to the enduring significance of his scholarship, he was recognized as one of the original four Doctors of the Church in the Western tradition.123