Rear Admiral Tiilikainen began his active duty on the former Osa II-class FAC, Tuima-class. He had his first command of the Tuima-class FAC 1994. He was assigned a command of Helsinki-class FAC 1995. He took command of the Missile Division of the Missile Sq 1996.

He graduated from the General Staff Officers Course 1999. After graduating he served as a deputy commander in the 6th Missile Squadron in Archipelago Sea Naval Command. In 2002 he reported to Department of Tactics and Operations Art at the National Defence University in Helsinki as an instructor of naval tactics. In 2005 he was assigned to the Archipelago Sea Naval Command as a Chief of Readiness. He served as a Chief of Operations in Archipelago Sea Naval Command 2007 – 2008. Rear Admiral Tiilikainen took
command of the 6th Missile Squadron in Archipelago Sea Naval Command 2008. Since December 2009 he served as a Chief of Strategic Plans section at the Navy Command Finland.

He was assigned to a post of Deputy Assistant Chief of Staff at the Plans Division (M5), Navy Command Finland, in which position he had the responsibility to coordinate the international activities of the Finnish Navy. He served as the representative of the Commander Finnish Navy in Defense Command Finland in Helsinki 2014 – 2015. From 2015 until August 2016 he served as a Chief of Staff of the Coastal Fleet. He was assigned to serve as Assistant Chief of Staff at the operations division (M3) of the Navy Command Finland until 31st of July 2017. He served as the Commandant of the Naval Academy Finland from 2017 until 2018. In 2019 he was assigned as the Chief of Staff in Navy Command Finland and between 2022 – 2023 he served as the Chief of Personnel (J1) in Defence Command Finland.

His professional background is on surface warfare area and his expertise includes operational and strategic planning and international cooperation. He was promoted to the rank of Rear Admiral 6th of December 2023.

Rear Admiral Tiilikainen has attended numerous international military courses including studies at the Naval Command College, Naval War College, USA, (NCC 2012) and US NWC’s Flag Level Combined Force Maritime Component Commander Course 2019.