During his military career, Pocius has held various positions, including Chief of Staff of Voluntary Service of National Defence, and Commander of the Lithuanian Land Force.

In 1979 after graduation from the reserve officer course in Kaliningrad, he gained the Soviet Army Mechanized infantry platoon leader qualification and was commissioned to the rank of lieutenant.

In 1988 while working in Lithuanian Physical Culture and Sports Committee as chief coach of judo and Sambo, Pocius joined Sąjūdis as a security guard in so called Green Armlet Group.

On 30 December 1991, as Deputy Chief of Staff of Voluntary Service of National Defence, Pocius was promoted to the rank of Major.

On 30 June 2004 Arvydas Pocius was promoted to the rank of brigadier general and was assigned as a commander of the Lithuanian Land Forces.

In autumn of the same year Pocius was assigned as Deputy Assistant Chief of Staff (DACOS) of the Joint Education and Training Sub-Division at the NATO HQ Allied Command Transformation.