The other lobbying effort in which Mr. Olson was involved occurred after Saudi Arabia, the Emirates, Bahrain and Egypt cut diplomatic ties with Qatar in 2017 and blocked flights and ships from Qatar from using their airspace and sea lanes. The rupture became an international crisis. American military officials had to scramble to deal with the consequences of the blockade because the U.S. military’s main air base in the Middle East is in Qatar.

Rex Tillerson, the first secretary of state under President Donald J. Trump, told U.S. lawmakers in 2019, a year after he had been forced out, that he had been taken by surprise by the diplomatic crisis. He said Jared Kushner, Mr. Trump’s son-in-law and a White House adviser, had spoken secretly with Saudi and Emirati leaders about their plans to impose the blockade during a visit to Riyadh in 2017.

Mr. Olson was paid to lobby officials in the Trump administration to encourage the U.S. government to help get the blockade lifted and repair diplomatic relations among the Persian Gulf nations, the Justice Department prosecutors said in their filing.

Qatar and the Emirates have poured money into Washington-based companies and research groups in recent years to try to influence U.S. policy. Thomas J. Barrack Jr., a friend of Mr. Trump, was arrested in July 2021 on charges of illegally lobbying for the Emirates. Elliott Broidy, a Trump ally and former Republican official, pushed for U.S. policies favorable to the Emirates while his private security company benefited from a $200 million contract with the country. And he was charged in 2020 with illegally lobbying for a Malaysian financier.

Mr. Olson received multiple awards during his more than three decades in the Foreign Service, according to an official online biography. He retired as a career minister, the second-highest rank in the service.

Mr. Olson was also posted in Mexico, Uganda, Tunisia, Saudi Arabia, Ethiopia and Iraq.

When Mr. Olson retired in November 2016, Mr. Kerry said in a statement, “Rick is quite simply one of our most distinguished diplomats, a career member of the Senior Foreign Service who has been on the forefront of our work in the Middle East, Africa and most recently in Afghanistan and Pakistan.”