Before he was appointed to the post, he served as the Malaysia's Assistant High Commissioner in Madras from 1963 to 1964, Second Secretary of Malaysia's Embassy in Paris in between 1966 and 1968, the Counsellor in the Malaysian High Commission in London from 1970 until 1972 and the Chargé d'affaires in Vientiane from 1974 until 1976.

After his tenure as Malaysian Ministry of Foreign Affairs' Deputy Secretary-General, he became increasingly involved with the United Nations.

In the past, he usually headed Malaysian diplomatic delegation to various regional and international bodies such as ASEAN and the Non-Aligned Movement.

Up until 2005, he was United Nations Secretary-General's Special Envoy to Myanmar and played a pivotal role in releasing Aung San Suu Kyi from house arrest in May 2002.

However, his impartiality as a UN Special Envoy was questioned by American officials in an embassy cable that was released via Wikileaks, alleging his business ties with the Burmese military regime.