Along with child emperors Dục Đức and Đồng Khánh, he had been taken in by Tự Đức who was unable to have children of his own. After the regicide of Emperor Hiệp Hoà the court regents acted quickly to install the fifteen year-old prince as the new Emperor. Kiến Phúc was quickly enthroned on 1 December 1883 at five o'clock in the morning. His predecessor, Emperor Hiệp Hoà, had been arrested and murdered while the French Superior Resident, Champeaux had left Huế. When he returned he angrily protested the hurried coronation of the new monarch and the fact that France had not been consulted. Champeaux used the Harmand Treaty signed by Emperor Hiệp Hoà on 25 August 1883 to justify his fury that the regents had not consulted Vietnam's new colonial masters before placing a new emperor on the throne. But the treaty in no way gave France any legal influence over the Imperial succession. However, the regents ignored this fact and stated that since Emperor Hiệp Hoà was dead the document was no longer valid. The French were not moved by this and further angered by Hiệp Hoà's death. Also, remember that the regents had killed Hiệp Hoà supposedly for not standing up to the French. However, when military plans began to take effect the two remaining regents quickly bent to the strength of France as well and made a formal request for the recognition of Kiến Phúc as the new Emperor.
Emperor Kiến Phúc managed to show that in him was potential for an effective "Son of Heaven." But he was hampered by poor health and corrupt regents, Nguyễn Văn Tường and Tôn Thất Thuyết. It was the Emperor's adopted mother, Học Phi, who held most of the authority, along with her secret liaison, regent Nguyễn Văn Tường. When the Emperor caught them he was enraged and declared, "When I get well, I will chop off your heads down to the third generation." Học Phi poisoned the Emperor's medicine. Kiến Phúc died on 1 August 1884. Early in 1885 the leader of the Imperial family council, Prince Gia Hung(Nguyễn Phúc Hông Hưu), began a secret investigation into Phúc's death. When Prince Tôn Thất Thuyết found out the truth, he was exiled and disappeared.
^Bruce M. Lockhart, William J. Duiker Historical Dictionary of Vietnam 2006 Page 189 "Kiến Phúc (1869-1884). Emperor (I. 1883—1884) in the Nguyễn dynasty. He was the last of three young rulers who succeeded each other on the throne after the death of their adoptive father Tự Đức. The rapid changes of emperor were the .. "