In a statement, Keeper of the Rulers' Seal Datuk Seri Syed Danial Syed Ahmad said the appointment would take effect on Dec 13, for a period of five years.
Sultan of Perak Sultan Nazrin Muizzuddin Shah was selected as the Deputy Yang di-Pertuan Agong for the same period.
The special conference attended by all the Malay rulers was chaired by Raja of Perlis Tuanku Syed Sirajuddin Putra Jamalullail.
The current Yang di-Pertuan Agong is Tuanku Abdul Halim Mu’adzam Shah, the Sultan of Kedah, whose five-year term as King effective from Dec 13, 2011 will end this Dec 12.
Tuanku Abdul Halim, 88, made history as the only Sultan who has been King twice in his lifetime.