 He first served at the royal library in Huế, and within one year was the district chief in both Thừa Thiên and nearby Quảng Trị province, presiding over seventy villages.Diệm was promoted to be a provincial chief (Tuần phủ) in Ninh Thuận at the age of 28, overseeing 300 villages.During his career as a mandarin, Diệm was known for his workaholism and incorruptibility, and as a Catholic leader and nationalist.