He started his military career as an officer cadet in 1980 and received his basic training at the
Sri Lanka Military Academy. He was commissioned as a second lieutenant in 1981 in the
Sri Lanka Light Infantry. He thereafter completed the Commando Officers Course, Infantry Young Officers Course and the Battalion Support Weapon Course. He had completed the Junior Command and Senior Command Courses at the
Army War College, Mhow. From January 1993 to January 1996, Ratnayake served as commanding officer of the 6th Battalion, Sri Lanka Light Infantry. He attended the graduated from
Defence Service Command and Staff College,
Bangladesh; the
National Defence University, China and the
Army Intelligence School,
Fort Huachuca,
United States. He has followed the Governance and Management of Defence Course at
Cranfield University,
UK, Higher Level Security Studies Diploma Course and Advanced Communication Skills Course in Asia-Pacific Centre for Security Studies in
Honolulu,
Hawaii, United States. He commanded the 6th Battalion Sri Light Infantry Regiment. He served as the General Officer Commanding of 23 Infantry Division in the
Eastern province. He played important roles in the operations of Liberations of Vakare and
Thoppigala. He also held the post of the Commissioner General Rehabilitation for rehabilitation of 12,000 ex-
LTTE combatants under the Bureau of the Commissioner General Rehabilitation. His other notable appointments include Commanding Officer of
Sri Lanka Military Academy and Director Media and Military Spokesman for the
Ministry of Defence. He was succeeded by Lieutenant General
Crishantha de Silva in February 2015. The outgoing commander was promoted to the rank of full general by President
Maithripala Sirisena. ==Later work==