Newly appointed National Security Adviser Robert O’Brien announced on Air Force One on Sunday Sept. 22 that Matt Pottinger, former top adviser on Asia for President Trump, will serve as the new deputy national security adviser.

O’Brien made the announcement while accompanying with the president to New York City for the United Nations General Assembly, the Hill reported. 

“I think Matt’s one of the most impressive young foreign policy/national defense/national security experts in the government,” O’Brien said. “He’s got a wonderful personality, I think he’s a team player. He’s going to help me bring some cohesion to the [national security council].”

Trump appointed O’Brien as his new national security adviser to replace John Bolton who had differences with the president on many issues. 

“Robert O’Brien is done a fantastic job for us with hostage negotiations,” President Trump said during a press conference with Australian Prime Minister Scott Morrison on Sept. 20 in the White House. “I think we can say that there has never been anybody that has done better than you and I as a combination.

“We’ve brought many people home, and we brought them home quickly,” he said. “So I think he’s going to do a great job.”

Pottinger has been a key person for Trump on important foreign policies. He arranged the summits between the president and North Korean leader Kim Jong Un.

Pottinger worked as a correspondent at The Wall Street Journal before. He enlisted in the Marine Corps in 2005 and served in Afghanistan and Iraq. Pottinger joined the Trump administration in 2017.