Nguyễn Trường Tộ was born into a Roman Catholic family in Nghệ An Province in central Vietnam, approximately in the year 1830 (from 1827 to 1830). His native village of Bùi Chu is part of present-day Hung Trung village in Hưng Nguyên district of Nghe An province. In his youth, Nguyễn Trường Tộ studied with lower-level degree holders and retired officials, earning a reputation in his region as an excellent Confucian scholar. However, he was not permitted to sit for the imperial civil-service examinations from which governmental officials were selected because of his Catholicism, which he never renounced. With the officially sanctioned road to prominence closed to him, Nguyễn Trường Tộ earned his living by teaching Chinese, first at home, and from 1848 onwards at Nhà chung Xã Đoài, a local Roman Catholic seminary. There his quick intelligence and classical learning garnered the attention of a French missionary, Bishop Jean-Denis Gauthier (1810–1877) of the Paris-based Société des Missions Etrangères (Foreign Missions Society). Gauthier began teaching him French and Latin as well as the basics of European science.