Throughout his extensive and distinguished career as a diplomat, Ku Jaafar has held various ambassadorial positions as a diplomatic administrative officer such as Second Secretary in the High Commission of Malaysia in Ottawa, Canada, Counselor at the Permanent Mission of Malaysia to the United Nations in New York, United States, Chargé d'Affaires in Croatia and Jordan, and Undersecretary for the Organization of Islamic Cooperation (OIC).

[3] His peak career as a diplomat was during his appointment as the 5th Secretary General of the D-8 Organization for Economic Cooperation, becoming the first Malaysian to hold the post.

Prior to that, Ku Jaafar was the highest diplomatic envoy of Malaysia to Egypt, Brunei, and Qatar.

Ku Jaafar has also served as the Director General for the Malaysian Institute of Diplomacy and Foreign Relations (IDFR).

[4] Currently, he sits as the chairman for Al-Ebreiz Global Capital Berhad, a public company listed in Bursa Malaysia that deals with shariah-compliant financing.