[1] Between 1983 and 1991 he served with the Black Sea Fleet as a platoon leader and battery commanding officer in the detached marine brigade.

In 1998 he assumed command of the 1st Detached Marine Brigade of the Ukrainian Navy, a position he held for five years.

[2] Ilyin was appointed to the post of Ukrainian Navy Commander on 27 July 2012[3][4] and promoted to the rank of Admiral on 24 August 2013.

[1][6][7] Shortly after Yanukovych fled the presidential palace, Ilyin issued a statement claiming, "As an officer I see no other way than to serve the Ukrainian people honestly and assure that I have not and won't give any criminal orders".

Ilyin was reported to have been admitted to hospital after suffering a heart attack on 27 February 2014;[citation needed] he was subsequently dismissed as Chief of the General Staff by the interim President of Ukraine, Oleksandr Turchynov.