Commodore Mamun joined Bangladesh Navy in 1989. He underwent basic naval training in German Naval Academy in 1989-1992, during which he obtained his commission. Thereafter, he completed various professional trainings in different institutions and sea-going vessels of Bangladesh Navy. In his mid-career, he attended Basic Intelligence Course from School of Military Intelligence and Junior Staff Course in Bangladesh Naval Academy. He served on board various warships of Bangladesh Navy in different capacities. He also did his Torpedo anti-submarine specialization in Pakistan. He underwent naval staff course in Defence Services Command and Staff College, Mirpur and a second staff course in Saudi Arabia. He served in two UN missions, namely in Eritrea and in Darfur.
Commodore Mamun is a graduate of National Defence College, Bangladesh where he attended Armed Forces War Course in 2014. At present, he is serving in Bangladesh Coast Guard Headquarters as Director of Plans and Acquisitions. He loves travelling and happily married, blessed with two sons.