[2] with concurrent accreditation as High Commissioner for Sri Lanka to Trinidad & Tobago and Ambassador (designate) to Mexico.

He entered the University of Peradeniya and obtained a Bachelor of Science (Hons) Special Degree in Mathematics in 1978.

In that match, Kariyawasam had figures of 3 for 22, including the prize wicket of David Gower, who went on to captain England.

Kariyawasam joined the Sri Lanka Foreign Service in 1981 and has served as a diplomat in Geneva twice (1983–1987, 2001–2004), Riyadh (1989–1992), Washington (1995–1998), New Delhi twice (1998–2001, 2009)[9] and New York (2005–2008).

[11] Ambassador Kariyasawam was the President of the Council of the International Organization for Migration (IOM) in the years 2001-2002.