Jayamanne received his appointment letter from the president at the Presidential Secretariat.

Jayamanne who worked at the Attorney General Department more than 25 years, has been serving as an Additional Solicitor General when he was appointed for the post of the Director General of the Commission to investigate allegations of Bribery or Corruption

He is a Graduate in Applied Science at Sri Jayawardenapura University. He completed his Postgraduate Degree at Oxford University. Jayamanne was a pioneer in introducing D. N. A. and telephone evidence for the legal process in Sri Lanka.