Tengku Muhammad Ismail was born on 1st March 1998 as the second child and first son of His Royal Highness Tengku Mizan Zainal Abidin, the Yang di-Pertuan Muda (Crown Prince) of Terengganu, and Cik Puan Sri Rozita Adil Bakeri. His father became the Sultan of Terengganu shortly after his birth, after which his mother became known as Permaisuri Nur Zahirah.
He was appointed as Yang di-Pertuan Muda (Crown Prince) on 12 January 2006.
After Sultan Mizan was elected as Yang di-Pertuan Agong, he appointed his son, Tengku Muhammad Ismail, then aged eight, as Regent on 12 November 2006. Because of Tengku Muhammad Ismail's young age, a Regency Advisory Council was established to discharge his duties for him. The council's members are Tengku Baderulzaman, Sultan Mizan's younger brother, Tengku Sulaiman Ismail, Sultan Mizan's uncle, and Federal Court judge Abdul Kadir Sulaiman. He was proclaimed as regent during a ceremony on 12 December.
As regent, he presided over the swearing in of Menteri Besar Ahmad Said following the 2008 general election.
His investiture ceremony as the patron of the state scout movement was held in 2009.
On 30th August 2010, he was proclaimed as the regent of Terengganu after he mukallaf that can carry his own responsibilities
On December 12, 2011, he welcomed the arrival of his parents after the end of their reign as King and Queen of Malaysia.