Hailing from Kurunegala, Miyanadeniya joined the newly formed Ceylon Army and received his basic training at Royal Military Academy, Sandhurst.
Promoted to lieutenant colonel, he was appointed commanding officer of the 1st Battalion, Gemunu Watch in July 1970 and lead the battalion through the 1971 JVP Insurrection, conducting counterinsurgency operations.
In December 1971, he took over as commanding officer of the 1st Battalion, Sri Lanka Sinha Regiment and served till April 1974.
He retired from the army having served as Director Training, on completing four years in the rank of Brigadier.
[1][2] His daughter married Major General Gratian Silva's son.