He achieved the highest position of regimental sergeant major (RSM) of the National Cadet Corps (Sri Lanka) in 1973.

Three months later he left the Company and joined the Sri Lanka Navy as an officer cadet and thus began a voyage that brought him to the pinnacle.

He went on to complete his basic training at Britannia Royal Naval College, Dartmouth as a Midshipmen and graduated in 1976 winning the Best International Midshipman Award along with appointment as Divisional Sub Lieutenant.

In 1998 he was the Aide de Camp (ADC) to HRH Prince of Wales, a fellow graduate of Britannia Royal Naval College, during his state visit to Sri Lanka for 50th Anniversary Independence Day Celebrations.

Samarasinghe's address earned high praise by the Chief of the United States Navy and all others present at the symposium, where he encapsulated the way ahead for 'Leveraging Cooperative Effort to Enhance Maritime Security Operations' by using a seven-step approach.

Naval chiefs of Australia, Bangladesh, India, Pakistan and UAE were on the same platform in Colombo for three days during the three main events attended by Mahinda Rajapaksa the President of Sri Lanka.

The presidential fleet review too was represented by large warships of Bangladesh, China, India, Iran, Pakistan, Russia and Thailand showcasing that Sri Lanka’s port of Colombo was a comfortable venue for such diversified representation, which is considered an unprecedented achievement.

[5] As director general for operations, at the Navy HQ, Samarasinghe successfully completed medical evacuations by sea that took place on 10 and 12 February 2009.

They displayed a strict discipline and respect of rules of engagement and at the same time very respectful and kind attitudes to help those in need.’[10] In July 2010, Samarasinghe was presented with a certificate of appreciation of the Government of Australia for the support and assistance rendered by efficient methods adopted to prevent human smuggling from the shore of Sri Lanka.

[citation needed] On 5 September 2011, speaking at the Australian Institute of International Affairs (AIIA), High Commissioner Samarasinghe stated that despite allegations made by various parties regarding the denial of humanitarian assistance to the people of the North of Sri Lanka during the last phase of the conflict, he was personally involved in coordinating the delivery of humanitarian assistance during that period.

Mr Ian Dudgeon, President of AIIA (ACT) said that the High Commissioner was an officer with a distinguished naval career and has received commendations for his conduct from international agencies such as the ICRC during the final offensives against the Tamil Tigers.