Colonel Pengiran Noor Rumaizi bin Pengiran Othman joined the Royal Brunei Armed Forces in 1996 and was then enlisted into the Officer Cadet School in 1997 at SAFTI Military Institute, Republic of Singapore. Upon commissioning as Second Lieutenant on 4th April 1998, he then served as a Platoon Commander at Third Battalion Royal Brunei Land Force.
Throughout his career in the Royal Brunei Armed Forces, he held various appointments in Command, Staff and Instructional, which among others includes Officer Commanding of Special Task Platoon, Adjutant, Aide-de-Camp and Staff Officer 2 to the Commander of the Royal Brunei Armed Forces, Company Commander, Aide-de-Camp to His Royal Highness Prince Haji Al-Muhtadee Billah ibni His Majesty Sultan Haji Hassanal Bolkiah Mu'izzaddin Waddaulah, the Crown Prince, Staff Officer of J5 (Joint Planning) and J7 (Joint Training) at Joint Force Headquarters, Officer Commanding at School of Infantry and Chief Instructor at Training Institute Royal Brunei Armed Forces as well as Military Assistant to Second Minister of Defence.
Colonel Pengiran Noor Rumaizi has attended various courses locally and at military institutions overseas which include Malaysia, Republic of Singapore, United Kingdom as well as the People's Republic of China. He attended the Executive Development Programme for Senior Government Officers in Brunei Darussalam with the collaboration between Ministry of Defence, Brunei Darussalam and the Lee Kuan Yew School of Public Policy, NUS in 2018, and the highly prestigious Senior Fellowship Programme for Public Service, Lee Kuan Yew, School of Public Policy, NUS in 2022. He completed the Royal College of Defence Studies, Global Strategy Programme (RCDS GSP) in International Security and Strategic Leadership Studies 2023/24 London, United Kingdom in July 2024. Notably, he also served in overseas mission as a member of Royal Brunei Armed Forces contingent at International Monitoring Team (IMT), Mindanao, Republic of the Philippines between 2007-2008.
Colonel Pengiran Noor Rumaizi graduated with Masters of International Security from Massey University, New Zealand in 2015 after the completion of his Command and Staff Course at Defence Academy Royal Brunei Armed Forces in 2014.
He is married to Nurol Faezah bte Mohd Faisal Al Sufri. Both of them enjoy hiking and running.