The 31-years-old royal lad is having sizable experience under his belt stretching from Yemen war to revamping the Saudi economy that is exploring new genres other than oil.
Mohammed bin Salman, who will take on Nayef's old job as interior minister, was relatively unknown in the kingdom when his father came to power 2 1/2 years ago.
Advertisements and proclamations have been churned out by public figures such as clerics and royals and businessmen in their thousands in a country where dissent against the absolute monarchy is nearly non-existent - but a full page advertisement taken out in a Saudi newspaper by McDonald's, wishing the promoted prince "peace and prosperity", has perplexed many people both inside the kingdom and internationally.
Saudi Arabia follows the ultra-conservative Wahhabi school of Sunni Islam, but sees Islamist militants as posing the biggest threat to its own stability. That visit helped lay the foundation for the president's visit to Saudi Arabia in May, making the kingdom his first global stop. For decades, the throne has passed from elderly brother to elderly brother - all sons of the late founder.
The royal decree said the decision by King Salman to promote his son and consolidate his power was endorsed by 31 out of 34 members of the Allegiance Council, made up of senior members of the ruling Al Saud family. His father is the governor of Saudi Arabia's Eastern Province, home to much of the country's oil wealth and most of its minority Shiites.
British Prime Minister Theresa May has welcomed the appointment of HRH Prince Mohammed bin Salman as the Crown Prince and Deputy Prime Minister of Saudi Arabia.
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It also questioned the appropriateness of the increase in the Sovereign Grant given it has already gone up 167 percent since 2012. The Queen will receive an 8% increase in her income from public funds after the Crown Estate posted a £24m rise in profits.
Another young prince also ascended to power on Wednesday.
Iran's leadership was critical of comments by the prince last month that the "battle" should be taken into Iran, with Supreme Leader Ayatollah Ali Khamenei labelling the Saudi leadership then as "idiots".
It is clear that Iran will respond to a more aggressive approach by the U.S. and its main Sunni Muslim-Arab ally in a confrontation. Iran and Saudi Arabia are embroiled in a regional struggle for political and religious influence.
"The elevation of Mohammed Bin Salman to the Crown Prince will likely mean minimal change to oil production policy but could bring more aggressive foreign policy moves that bring back the political risk premium", said a research note published by RBC Capital Markets. 'I will rest now and God help you, ' he said.
Mohammed's youth is a novelty for a country used to ageing leaders - King Salman is 81 and his predecessor King Abdullah died in 2015 aged around 90.