He was granted the title Thọ Xuân Công (壽春公 "Duke of Thọ Xuân") and appointed Right Director of Imperial Clan Court (Tôn Nhân Phủ Hữu Tôn Chính 尊人府右尊正) in 1830.
In 1885, Tôn Thất Thuyết launched a failure ambush against French colonists, and escaped from Huế together with Emperor Hàm Nghi.
During the emperor's absence, Miên Định was appointed as puppet "Prince Regent" (giám quốc) by French general Henri Roussel de Courcy.
In September, de Courcy exiled Tường to Poulo Condore, and installed Đồng Khánh as new emperor.
He died in the next year, and received the posthumous name Đoan Khác (端恪).