Lieutenant General Athanasios Sardellis was born in Athens, Greece in 1966. He was admitted to the Military Academy in 1984 and graduated as an Artillery Second Lieutenant in 1988.

Lieutenant General Athanasios Sardellis served in various Field and Air Defence Artillery Units, assuming various levels of command positions to include Ground Based Air Defence (GBAD) Battery Commander, GBAD and PzH2000 Howitzer Battalion Deputy Commander. In 2006 he was assigned as Commander of a GBAD Artillery Unit.

Other positions he has been assigned to, include

Staff Officer Logistics Plans/Ops and Chief of International Affairs Section, B’ Corps (Rapid Reaction Corps) (Veria)
Staff Officer Plans and Ops, NATO Rapid Deployment Corps – Italy (Milan)
Chief Air Defence Artillery and Deputy Director, Artillery Directorate, Hellenic Army General Staff.
Director, Office of the Deputy Chief, Hellenic Army General Staff
Brigade Deputy Commander of the 80th Brigade “KOS”
Chief of National Defence Planning Section, Directorate of Strategic Defence Planning, Hellenic National Defence General Staff
Director, Office of the Chief of Staff, Hellenic Defence General Staff Office
Commander of the 96th Brigade “CHIOS”.
Commander of NATO Missile Firings Installation (NAMFI), Crete.
Artillery Director, Hellenic Army General Staff.

In 2024 he was promoted to Lieutenant General and was assigned as Commander of the Hellenic National Defence College

Lieutenant General SARDELLIS has attended all the Hellenic Army Artillery Schools and the Hellenic Army War College. He graduated from the Chemical Officer Basic Course at the US Army Chemical School, GBAD Evaluation and Operations as well as Force Generation Planning Courses at
NATO School, Oberammergau Germany. He holds a Diploma from the Hellenic National Defence College and a Masters of Arts in Applied Strategy and International Security from the University of Plymouth.

Lieutenant General SARDELLIS has been awarded all the Hellenic Army decorations and medals for his rank. In 2015 The United States Field Artillery Association announced him a member of the Honorable Order of Saint Barbara while in 2020 His Eminence Metropolitan Markos of Chios, Psara and Oinousses awarded him with St. Isidoros Cross.

Lieutenant General SARDELLIS speaks English and Italian. He is married to Helena and they have two children aged 30 and 27.