Sultan Ibrahim Sultan Iskandar was sworn in as Malaysia's 17th king in a ceremony at the national palace in Kuala Lumpur on Wednesday.
In a televised ceremony Ibrahim took his oath and signed the instruments of office with the country's other hereditary rulers witnessing the event.
Sultan Nazrin Shah, ruler of Perak state, will serve as the deputy head of state for the next five years.
Prime Minister Anwar Ibrahim was present at the ceremony along with his cabinet ministers to witness the swearing-in of the new king.
His appointment came after his predecessor Sultan Abdullah Sultan Ahmad Shah, ruler of Pahang state completed his term on Tuesday.
Malaysia is a constitutional monarchy, with nine sultans or rulers, who head their respective state and act as the religious leader, taking turns to serve as the king for a five-year term.