Vice-Admiral Arnaud Coustillière's career was essentially divided into operational shipboard embarkations and commands, and senior positions in central administration, with a special focus on telecommunications and cyber defense.

He was appointed General Officer for Cyber ​​Defense on July 1, 2011 when the position was created. Directly attached to the Deputy Chief of Operations of the Military Staff, and under the dual tutelage of the Chief of the Defense Staff and the Minister's Military Chief of Staff, he is responsible for the Ministry's cyber defense. and his conduct in a cybernetic crisis.

In February 2011, consistent with the extension of ANSSI's missions, he was appointed "Cyber ​​Defense" Project Manager with the "Operations" Deputy Chief, while temporarily retaining his previous duties. He has been with the army staff since the summer of 2008 and has been an operational coherence officer in charge of telecommunications and cyber defense.

He is Knight of the Legion of Honor and Officer of the National Order of Merit. He holds the Cross of the Fighter, the Overseas Medal (Middle East), the National Defense Medal, and various commemorative medals from the theaters of foreign operations.