Lieutenant Colonel Fakhrul Ammar bin Haji Mohammad Isa began his military career when he enlisted into the Royal Brunei Armed Forces (RBAF) on 09 April 2001. After undergoing his Basic Military Training at Training Institute RBAF, he continued his Officer Cadet Training at the Royal Military Academy Sandhurst, United Kingdom and commissioned as an Officer in 2003.
Throughout his military career, Lieutenant Colonel Fakhrul Ammar has held various command appointments in RBAF. His command appointments include; Platoon Commander of Rifle Company and Mortar Officer of Second Battalion Royal Brunei Land Force, Adjutant of Training Institute Royal Brunei Armed Forces, Second in Command and Officer Commanding of B Company First Battalion Royal Brunei Land Force, Intake Commander of Officer Cadet School Defence Academy Royal Brunei Armed Forces and Second in Command of Third Battalion Royal Brunei Land Force before he assumed the appointment of Commanding Officer of First Battalion Royal Brunei Land Force on 4th December 2020.
Lieutenant Colonel Fakhrul Ammar has attended various military courses throughout his service. Among the courses, he attended Regimental Signal Officer Course, Mortar Platoon Commander Course, Junior Staff Course, Battalion Tactics Course, and the 9th Command and Staff Course. Lieutenant Colonel Fakhrul Ammar was honoured and awarded with 'Pingat Laila Tugas' in 2002 and 'Pingat Jubli Emas' in 2011.
Lieutenant Colonel Fakhrul Ammar bin Haji Mohammad Isa is married to Hajah Adina Hazri binti Haji Azahari and they are blessed with two daughters and two sons.