After a long and distinguished career as the Senior Professor of Sinhala. In 2007, Prof. J.B Disanayaka was appointed as the Ambassador of Sri Lanka to Thailand, Laos, and Cambodia. He served as a diplomat for four years. 

During this time, he was awarded the ‘Friend of Thailand’ by the Tourism Authority of Thailand, in recognition of his contributions. This was the first time this award was given to a Sri Lankan.

මහාචාර්ය ජේ.බී දිසානායක, තායිලන්තය, කාම්බෝජය හා ලාඕසය යන රටවල ශ්‍රී ලංකා තානාපති වශයෙන් 2007 දී පත් කරනු ලදුව,වසර හතරක් රාජ්‍ය තාන්ත්‍රිකයෙකු වශයෙන් සේවය කළේය.