He took part in athletics and rugby, and was a Regimental Sergeant Major of the College Cadet Corps.

Seneviratne joined the Ceylon Army after completing his schooling on 1 October 1951 as a cadet officer and received his basic training at Royal Military Academy, Sandhurst from 12 January 1952 to 2 July 1953.

He thereafter attended the Young Officers course at the Royal School of Military Engineering in Chatham before returning to Ceylon.

[1][2] He was appointed commanding officer of the 1st Field Engineer Regiment on 6 December 1970, serving till 16 May 1977.

[1][2] On 11 February 1985, he was appointed the 10th commander of the Sri Lanka Army and promoted to the rank of major general.

[4] He died August 12, 2009, aged 78 and last rites carried out with full military honours at the Borella General Cemetery.