On 29 December 2008, The Council of Undang proclaimed him as the 11th Yang di-Pertuan Besar of Negeri Sembilan succeeding Almarhum Tuanku Jaafar ibni Almarhum Tuanku Abdul Rahman who had died on 27 December 2008. It has been learnt that many prominent Malaysians had backed Tuanku Muhriz to succeed as the Ruler of Negeri Sembilan in view of his modest and dignified personality and by his having a successful corporate career. He was also the rightful heir, by tradition, to the throne on the death of his father.