[1] Educated at Royal College, Colombo, Jayasinghe joined the army in 1978 as an Officer Cadet, and was commissioned into the 1st Reconnaissance Regiment, Sri Lanka Armoured Corps in 1980 as a Second Lieutenant.

He was appointed as the Chief Instructor of the Sri Lanka Military Academy and was hand-picked to be the first Chief Instructor of the Army Command and Staff College which was the precursor to the Defence Services Command and Staff college.

[2] Following his retirement he was an Executive Group Director of The Capital Maharaja Organisation Limited and the General Manager of Human Resources of Union Assurance PLC.

[3] He then functioned as the consultant for Human Resources at SLINTEC, a leading nanotechnology company in Sri Lanka.

Having served 4 Years at SLINTEC, he joined Citizen's Development Business Finance PLC as (again) a Consultant in HR.