That spring, only a few months later, Mr. Kushner successfully pushed for his father-in-law to make his first international trip to a summit in Riyadh, the Saudi capital, where the president was photographed participating in a traditional sword dance. Around the same time, Mr. Kushner personally helped negotiate a 10-year agreement for Saudi Arabia to buy more than $110 billion in American weapons. Prince Mohammed was named crown prince that June.
Mr. Kushner and Prince Mohammed regularly and informally communicated by text message, and they addressed each other by first name. After the Khashoggi killing, Mr. Kushner defended Prince Mohammed within the White House, despite intelligence reports showing his involvement in the plan to execute the journalist.
In a move widely interpreted as an attempt to protect the prince, Mr. Trump kept those reports classified throughout his term. They were unsealed this year by President Biden, who has called Saudi Arabia a “pariah” and has adopted a much cooler approach to the kingdom than his predecessor.
While in the White House, Mr. Kushner devoted much of his energy to trying to enlist Arab states in a grand bargain to provide economic benefits to the Palestinians in exchange for Palestinian concessions to Israel. Although that attempt was no more successful than previous efforts at Middle East peace, his talks with the Emiratis and a few neighbors ultimately yielded the more limited Abraham Accords on normalizing relations with Israel.
Mr. Kushner has adopted a low profile since leaving the White House. Along with his wife, Ivanka Trump, and their children, he relocated to Miami, beyond the media glare of New York and Washington. He established Affinity there in recent months.
He has told associates that he has no desire to re-enter politics. Seeking to build on pacts he helped negotiate in government, Mr. Kushner started the Abraham Accords Institute for Peace, a nonprofit group that will seek to expand trade ties between Israel and its Arab neighbors.
Mr. Kushner also hopes that his new firm, Affinity, will find opportunities in cross-border investing in the Middle East, the person with knowledge of the firm’s plans said. One key area of interest, this person said, is to build investment relationships between Israel and Saudi Arabia.