He began his career in an international bank in Malaysia and became a director and shareholder of a company licensed as brokers in interbank foreign exchange and in the currency deposits market (1973–1986).

It has been suggested that the then Prime Minister of Malaysia, Tunku Abdul Rahman, influenced the Undangs not to choose Tuanku Muhriz on account of his youth (he was then only nineteen).

On 4 May 1974, Yang Maha Mulia Tuanku Ampuan Durah held a royal couples' traditional departure ceremony (istiadat keberangkatan pulang pengantin diraja) at the Istana Lama Seri Menanti.

Many prominent Malaysians backed Tuanku Muhriz to succeed as the Ruler of Negeri Sembilan in view of his modest and dignified personality and by the fact that he had a successful corporate career.

[citation needed] Due to having kept a low profile, Tuanku Muhriz was largely unknown outside royal circles in Negeri Sembilan.

Throughout his life Tuanku Muhriz established and maintained strong ties with the Undangs, the general nobility, the lesser royalty and people of Negeri Sembilan, and more so since moving back to the state.

He also has powerful backers within the political establishment in the state, with the former Menteri Besar Tan Sri Mohd Isa Abdul Samad among his supporters.