Philippe Vannier entered the service of Nguyễn Ánh in 1789 following the encouragements of Mgr Pigneau de Béhaine.[3] In 1790, Nguyễn Ánh gave him the command of one of his ships. In 1792 he was in command of a warship furnished by Jean-Marie Dayot, and fought at the battle of Qui Nhơn.[2] In 1800, Philippe Vannier was commander of the Phoenix (Phuong-Phi), the largest ship of Nguyễn Ánh's navy, with 26 guns and 300 men.[2][4] In April 1801, he again fought in front of the harbour of Qui Nhơn, and was nominated General (Brigadier) of the Navy.[2] The battle opened the way for Nguyễn Ánh's invasion of northern Vietnam.[4]
His second-in-command was another Frenchman, Renon, from Saint Malo.[2]
After the end of the war in 1802 and the victory of Nguyễn Ánh, Philippe Vannier remained in the service of the Vietnamese emperor, as a Mandarin. He married a Vietnamese Christian woman named Madeleine Sel-Dong, with whom he had several children.[4] He served Nguyen under the name Nguyen Van Chan until 1826,[1][5] but then left Vietnam at the same time as Jean-Baptiste Chaigneau, soon after the accession of Minh Mạng to the throne.
Philippe Vannier died in Lorient on 6 June 1842.[4] His Vietnamese wife died in the same city on 6 April 1878.[4]
One of their grandsons, Emile Vannier, was a Navy officer who participated to the Cochinchina campaign in 1863–1864, and died in 1885.[4]