Bentégeat studied at the military academy École spéciale militaire de Saint-Cyr, where he enrolled in 1965 and graduated in 1967. After graduation, he first served with the Troupes de marine, which is a part of the French Army. From 1990 to 1992, he served as Assistant Defence Attaché in Washington, D.C. He served as Assistant to the Chief of the Military Staff of the President of the Republic from 1993.
Bentégeat was promoted to the rank of Brigade General in 1996 and to Divisional General (equivalent to Major General) in 1998, when he became assistant to the Director for Strategic Affairs of the French Ministry of Defence. In April 1999, he was assigned as Chief of the Military Staff of the President of the Republic, was promoted to Général de corps d'armée (equivalent to Lieutenant General) on September 1, 1999 and to Général d'armée (full General) on January 4, 2001. He became Chef d'état-major des armées (Chief of the Defence Staff) in October 2002.