Lorenzo D'Addario attended the Nunziatella Military School in Naples and the Military Academy in Modena. Assigned to the Parachute Infantry of the Folgore Airborne Brigade, in Tuscany, he served as Rifle Platoon and Company Commander in the 11^th Rifle Company, then Commanding 5^th Parachute Battalion, 186^th Parachute Regiment in Siena and ultimately the Brigade, in Livorno.

A graduate of the Advanced Command and Staff Course 1 at the Joint Services Command and Staff College, in Bracknell, UK, he served as Staff Officer Training in HQ 3 (UK) Division, Staff Officer Doctrine in the Army General Staff, Chief of the Staff Operations Section of the Deputy Chief of Defence, Military Assistant to the Commander of the Joint Operations HQ, Executive Assistant to Deputy Supreme Allied Commander Transformation, Deputy Chief Land Transformation Department of the Army General Staff, Deputy Head of the Italian Defence General Staff Plans and Policy Division, in charge of Strategic Direction and Policy on NATO, EU and multinational initiatives, Deputy Commander Allied Rapid Reaction Corps in Innsworth, UK.

He deployed as a unit commander in Operation Provide Comfort, in Northern Iraq, the Military Support to Civilian Authorities Operation in Sicily, the United Nations Operation in Somalia II, and as Battalion Commander, Multinational Brigade South-West, Kosovo Force, as part of Operation Decisive Endeavour, and to Afghanistan, in the Districts of Bakwa and Gulistan, as Commander Task Force South-East, ISAF Regional Command West. He served as Commander KFOR XXIII.

He is married with Julia. They have two children, Elisabetta and Giovanni.