[2] Aslan was not only considered to be powerful member of the late Hafez al-Assad's inner circle, but he was also regarded by outside observers as having significantly improved Syrian military readiness while operating under severe financial constraints.

His breakthrough came in November 1970 when he supported the military coup that brought Hafez al-Assad to power in Syria, and he was designated leader of the 1st and 5th Infantry Divisions of the Syrian Army.

[7] He became in charge of the Syrian Army contingent involved in Lebanon from 1976 to 1979, supervising the "hundred days war" against the Christian militia of Bachir Gemayel.

[2][9] Aslan was a proponent of mandatory conscription for Syrian men, and was the main negotiator for arms deals with suppliers around the world, including Russia, China, Armenia, North Korea and Iran,[10] as well as military treaties with Japan and several Eastern European countries.

[14] However, he was relieved from his post as chief of staff by Bashar al-Assad in January 2002, as part of the younger president's program of reform[2] and after reported clashes with Assef Shawkat[10] regarding personnel changes.