Lieutenant Colonel Mohammad Salehudin bin Dato Paduka Haji Puasa enlisted to the Royal Brunei Armed Forces in May 2000 and was commissioned from the Officer Cadet School, SAFTI Military Institute Singapore in 2001. Throughout his career, he had held various appointments: Infantry Platoon Commander, C Company, 1st Battalion Royal Brunei Land Force (2001-2002), Regimental Signal Officer, 3rd Battalion Royal Brunei Land Force (2002-2004), Operational Tour with 1st International Monitoring Team, Mindanao, Philippines (2004-2005), Staff Officer, Defence Minister’s Office & Directorate of Strategic Planning, Ministry of Defence (2005-2011), SO2 Defence Security Branch, Defence Minister’s Office & Directorate of Strategic Planning, Ministry of Defence (2011-2014), Second in Command of the 2nd Battalion Royal Brunei Land Force (2014-2016), Assistant Chief of Staff Plan, Royal Brunei Land Force Headquarters (2016-2019), Head of Leadership and Management Centre, Defence Academy, Royal Brunei Armed Forces (2019-2020) and Senior Directing Staff (2020-present).
As for career courses, he had attended the Platoon Commander Course in 2002 (Training Institute RBAF), Junior Staff Course in 2006 (Training Institute RBAF), Mid-Career Course in 2007 (School of Infantry, Quetta, Pakistan), 4th Command and Staff Course in 2014 where he was awarded the RBAF Commendation Award (Defence Academy, RBAF) and the 14th Executive Development Programme in 2017 (Sultan Haji Hassanal Bolkiah Institute of Defence and Strategic Studies, MINDEF/Lee Kuan Yew School of Public Policy, NUS, Singapore). Lieutenant Colonel Mohammad Salehudin academic qualifications are BTEC HND Business and Finance from City College of Higher Education, United Kingdom, BA (Hons) Business Studies from University of Glamorgan, United Kingdom and MA International Security from Massey University, New Zealand. In 2007, he was awarded the Meritorious Service Medal (PJK – Pingat Jasa Kebaktian) and in 2012, The Most Blessed Order of Setia Negara Brunei 4th Class (PSB – Darjah Setia Negara Brunei Yang Amat Bahagia Darjah Keempat)) from His Majesty Sultan Haji Hassanal Bolkiah Mu'izzaddin Waddaulah, Sultan and Yang Di-Pertuan of Brunei Darussalam.
Lieutenant Colonel Mohammad Salehudin is married to Hajah Seri Ainey binti Haji Shahri. His interests includes a variety of sports and travelling.