When his father dies, Crown Prince Mohammed will become something Saudi Arabia has never seen — a young ruler set to stay in power for decades.
He has also reportedly become friendly with another powerful millennial, Trump's son-in-law and senior adviser Jared Kushner.
As defense minister, Crown Prince Mohammed has also met several times with Defense Secretary Jim Mattis.
He has struck up a strong relationship with the new administration, meeting with President Donald Trump early in his presidency.
Crown Prince Mohammed "struck us as extremely knowledgeable, very smart," former President Barack Obama told the Saudi-owned Al Arabiya network. "I think wise beyond his years."
Crown Prince Mohammed started developing ties to the US early on. King Salman sent Crown Prince Mohammed as one of two delegates to the US when the monarch pulled out of a 2015 Gulf summit.
With these two men out of the picture, Crown Prince Mohammed effectively controls the three pillars of Saudi Arabia's security apparatus — the Ministry of Defense, the Ministry of the Interior, and the National Guard — in an unprecedented consolidation of power.
Additionally, one of the biggest names implicated in the recent anti-corruption arrests was Prince Mutaib bin Abdullah, the head of Saudi Arabia's National Guard.
Prince Mohammed bin Nayef was crown prince and interior minister until June 2017, when Prince Mohammed took over.
As he's gained influence, Crown Prince Mohammed has started to edge out some major Saudi power players.
He was also seen to be behind the landmark decision earlier this year to allow Saudi women to drive.
Crown Prince Mohammed has made headlines recently for wading into Saudi Arabia's culture wars, calling for a return to "a more moderate Islam."
More recently, in October, he announced a $500 billion mega-city that will be powered completely by renewable energy, called NEOM.
In 2016, Crown Prince Mohammed announced a long-term economic plan, called Vision 2030, which aims to remove Saudi Arabia's economic dependence on oil.
Along with his role as defense minister, Crown Prince Mohammed was also given control of Saudi Aramco, the kingdom's state-owned oil company.
Each of these moves can be viewed as part of a broader campaign to increase pressure on Saudi Arabia's regional rival, Iran.
Although it's still unclear, there are reports that Crown Prince Mohammed had a large part to play in Saudi-linked Lebanese Prime Minister Saad al-Hariri's resignation, submitted while he was in Saudi Arabia this weekend.
Crown Prince Mohammed has also reportedly been a driving force behind the Gulf countries' efforts to isolate Qatar.
As defense minister, he has become the leading backer of Saudi Arabia's ongoing war with Houthi rebels in Yemen.
He was 29 years old when he took on the job. Now 32, Crown Prince Mohammed remains the world's youngest defense minister.
Crown Prince Mohammed first made international headlines in January 2015, when he took over for King Salman as defense minister when his father ascended to the throne following the death of King Abdullah.
That doesn't mean he's not impulsive, though. Crown Prince Mohammed reportedly bought a yacht, the Serene, for approximately 500 million euros after spotting it while vacationing in the south of France. The former owner, Russian vodka tycoon Yuri Shefler, moved off the yacht that day.
Despite his supposedly lacking background, Crown Prince Mohammed reportedly was angling for a future in government. "It was obvious to me that he was planning his future — he was always very concerned about his image," a family associate told The New York Times, noting that Prince Mohammed did not smoke, drink alcohol, or stay out late.
Crown Prince Mohammed likes water sports, such as water skiing, as well as iPhones and other Apple products, according to the New York Times profile. The article also notes that Japan is his favorite country and he visited there on his honeymoon.
Crown Prince Mohammed holds a bachelor’s degree in law from King Saud University in Riyadh and served in various advisor roles for his father.
A 2015 New York Times article details how unexpected his rise has been, noting that his three older half-brothers "all have distinguished résumés and were once considered contenders for top government roles."
Not much is known about Crown Prince Mohammed's early life. He is the eldest son of King Salman’s third wife, and reportedly spent much of his time shadowing his father.