He is a commissioned officer in the US Naval Reserve and has served on active duty in Kosovo, Bosnia and Herzegovina, and on the Joint Staff in the Pentagon.
Amerikan Deniz İhtiyat Teşkilatında muvazzaf subay olan Gregorian, Kosova ve Bosna Hersek’in yanı sıra Pentagon’daki Müşterek Karargah’ta aktif görevde bulundu.