In 1935, he became aide-de-camp to his elder half brother Sultan Sulaiman Badrul Alam Shah, accompanying him to the coronation of King George VI on 12 May 1937.On 18 October 1943, the Thai government under Prime Minister Plaek Phibunsongkhram took over the administration of Terengganu from the Japanese and continued to recognise Sultan Ali Shah.Sultan Ismail's reign was at a time when Malaysia began to be active internationally, having secured a more solid foundation as a Federation of Malay States, Sabah and Sarawak.Many visits by world leaders were made including US President Lyndon B. Johnson, West German President Heinrich Lübke, King Faisal of Saudi Arabia, the Shah of Iran, Emperor Haile Selassie of Ethiopia, Ferdinand Marcos of the Philippines, General Ne Win of Burma and Prime Minister Nguyễn Cao Kỳ of South Vietnam.[13] Sultan Ismail was reigning as Yang di-Pertuan Agong when the May 13 incident sparked race riots in Kuala Lumpur and parliament was suspended.