Brigadier Duncan Mann commissioned into the Parachute Regiment in 1999, and served in various regimental appointments in Sierra Leone, Northern Ireland and Iraq. He also trained junior soldiers at the Army Foundation College Harrogate.
Following the Intermediate Command and Staff Course (Land) he combined his engineering degree and infantry experience as a requirements manager in the training and simulation projects team in Defence Equipment and Support (DE&S) delivering urgent operational requirements to Afghanistan. He then returned to regimental duty as a sub-unit commander serving in Afghanistan before running the Platoon Commanders’ Battle Course at the Infantry Battle School.
Having graduated from the Advanced Command and Staff Course, he served as a staff officer in the MOD before taking command of 2nd Battalion of the Parachute Regiment in 2016. In 2018 he returned to DE&S and was selected to promote and lead the Dismounted Close Combat portfolio acquiring and supporting infantry capabilities. From 2021 to 2023 he commanded the Land Regional Hub and British Army Training Unit in Kenya where he validated light role battlegroups and coordinated training and capacity building with allies and partners across East Africa. On returning to the UK he was assistant head for ground manoeuvre in the Army Futures directorate, responsible for the capability planning of all manoeuvre brigades and combat units.
He assumed the appointment of Deputy Commanding General Operation INHERENT RESOLVE in October 2025.
Brigadier Mann is married with two children. He enjoys military history, hill walking and running.