President Donald Trump said the first day of his maiden international trip has been "tremendous".
Mr Trump was largely kept away from reporters during a busy day of meetings and ceremonies in Riyadh, Saudi Arabia.
But late in the day, he said deals the US government and private sector reached would lead to "tremendous investments" in the United States.
He said the deals will also create "jobs, jobs, jobs".
Mr Trump has agreed to a defence cooperation deal with the Saudis, pledging 110 billion US dollars effective immediately and up to 350 billion US dollars over 10 years.
There are some private sector agreements, too.
The military package includes tanks, combat ships, missile defence systems, radar and communications, and cybersecurity technology.
Mr Trump and Saudi King Salman signed a series of agreements cementing their countries' military and economic partnerships.
Mr Trump arrived in Riyadh after an overnight flight and was welcomed at an elaborate airport ceremony by Saudi King Salman.
He is the only American president to make Saudi Arabia, or any majority Muslim country, his first stop overseas, a choice designed in part to show respect to the region after more than a year of harsh anti-Muslim campaign rhetoric.
Mr Trump will also travel to Israel, have an audience with Pope Francis at the Vatican and meet with allies at a Nato summit in Brussels and the G7 in Sicily.
He waved from the doorway after Air Force One touched down and before descending the staircase with first lady Melania Trump.
Several jets then flew overhead leaving a red, white and blue trail.
At a later ceremony at the grand Saudi Royal Court, the king placed the Collar of Abdulaziz Al Saud, the nation's highest civilian honour, around Mr Trump's neck.
The medal, given to Mr Trump for his efforts to strengthen ties in the region, has also been bestowed on Russian president Vladimir Putin, Prime Minister Theresa May and Mr Trump's predecessor, Barack Obama.
The king and Mr Trump were overheard discussing natural resources and arms, and the king bemoaned the destruction caused by Syria's civil war.
White House officials hope the trip, complete with images of the accompanying pomp and pageantry of a president abroad, will help Mr Trump recalibrate after one of the most difficult stretches of his young presidency.
The White House bungled the president's firing of FBI Director James Comey, who was overseeing a federal investigation into possible ties between Mr Trump's campaign and Russia. This week, the Justice Department relented to pressure from Democrats and named former FBI chief Robert Mueller as special counsel to lead the probe.
But fresh news reports about the Russia investigation surfaced shortly after Mr Trump departed and threatened to overshadow the nine-day trip.
The New York Times reported that Mr Trump called Mr Comey "a real nut job" while discussing the ongoing investigation with two Russian officials in the Oval Office earlier this month.
He also told them that firing Mr Comey had "taken off" the "great pressure" he was feeling from the investigation, the Times reported.
Meanwhile, The Washington Post reported that an unidentified senior Trump adviser was being considered a "person of interest" in the investigation. Separately, Mr Comey agreed to testify at an upcoming, open hearing of the Senate intelligence committee, the panel said.
Despite those troubles, Mr Trump was warmly received in Saudi Arabia in contrast to his predecessor. Saudi's ruling family grew deeply frustrated with Mr Obama's detente with Iran and his restrained approach on Syria.
The king did not greet Mr Obama at the airport when he visited last year.
Billboards featuring images of Mr Trump and the king and emblazoned with the motto Together We prevail, dotted Riyadh's highways, and Mr Trump's hotel was bathed in red, white and blue lights and, at times, an image of the president's face.