The crown prince oversaw the invasion of Yemen as defense minister in 2015. Some members of Congress have been critical of the Saudi involvement, particularly over the humanitarian situation and civilian casualties.
Riyadh expressed its nuclear ambitions in 2009 when a royal degree said that "the development of atomic energy is essential to meet the Kingdom's growing requirement for energy to generate electricity".
He is on a public relations blitz while traveling in the United States, with stops in New York, Boston, Seattle, Los Angeles, San Francisco and Houston.
When the crown prince visited London earlier this month, Saudi Arabia and Britain signed a letter of intent to finalise talks on a multi-billion-pound order for 48 Typhoon fighter jets.
Moreover, it is not true that the U.S. is an open market for whoever wants to buy weapons, as some comments on President Trump's statement - when he talked about arms sales in the presence of the Saudi crown prince - suggested.
Another point of friction is the war in Yemen, where Saudi Arabia leads a coalition fighting the Iran-backed Huthi rebels. Yemen is the latest such example where USA forces provide logistical and intelligence support to a Saudi-led coalition of largely Gulf nations fighting to oust Houthi rebels from what was already the Arab world's poorest nation before the conflict began. The already strong relationship between the two countries is being reinforced during meetings with President Donald Trump and senior officials.
They also discussed nuclear cooperation. "The relationship now is probably as good as it's really ever been and I think will probably only get better". He has allowed women to drive and opened movie theaters shuttered since the 1980s, advocating a more moderate brand of Islam than that which has dominated Saudi life for the last four decades. He said a ten year window for implementing the deal was under way.
A key focus of his visit will be any information on a potentially lucrative listing of up to 5 percent of Saudi oil firm Aramco. And on Tuesday, the Saudi Crown Prince had dinner - not with Tillerson's apparent replacement, but, rather, with Trump's son-in-law, Jared Kushner.
"You were the crown prince, and now you are beyond the crown prince", he said, before adding that he misses Mohammed's father, King Salman, and hopes to see him soon.
But he's also asserted power in the Middle East in an altogether new way for a Saudi monarch, detaining some of his country's richest and most powerful men in a stunning anti-corruption campaign that netted over $100 billion.
Trump says Saudi Arabia is "footing a big part of the bill" for defense in the Middle East.