Jonny Mortimer Hendry attended the Royal Military Academy Sandhurst (RMAS) from January 2008 until December 2008.
Following this he commissioned into The Parachute Regiment. From 2009 to 2011, he was Platoon Commander of 12 Platoon, D Coy, 2 PARA. Whilst in this post he deployed to the Falklands, Kenya, Jungle Warfare Instructor Course Brunei and Afghanistan on Op Herrick XIII (PB1, Nar-e-saraj and Helmand)
He was then promoted to Captain aged 23. Captain Mortimer Hendry was the youngest Captain in the British Army at the time. From 2011 to 2013, Capt Mortimer Hendry was a Platoon Commander with SFSG (Special Forces Support Group) on Herrick XV/XVI. During this time he was Mentioned in Despatches.
After this, Capt Mortimer Hendry became Officer Commanding of 3 PARA Mortars, deploying to Spain and Kenya. He also deployed to Mongolia with the UN.
He left the British Army in November, 2014.