Educated at Royal College, Colombo,[1] Jayatilleka joined the army after completing his schooling and was commissioned as a Second Lieutenant in the Sri Lanka Artillery, following his training at the Sri Lanka Military Academy.

Following orders from the GOC 54 Division to make a strategic withdrawal of troops from Elephant Pass due to a lack of water, Colonel Jayatilleka withdrew his troops in order.

He died of dehydration on April 22, 2000, at the Palali Military Hospital.

Jayatilleka was married to the daughter of the former army commander General Hamilton Wanasinghe.

His brother Captain Nalin Jayatilleke was killed in 1993 serving as a forward observation officer.