The House Select Committee investigating the Jan. 6 Capitol Riot will hold the last of its planned summer hearings on Thursday evening. The hearing will include testimony from two former President Donald Trump aides, who had resigned after the riot.

One of the aides is Matthew Pottinger, a former journalist and Marine Corps officer, who served closely under Robert O'Brien, Trump’s last national security advisor. He will appear alongside former White House deputy press secretary Sarah Matthews, who similarly resigned after Jan. 6.

Pottinger, 49, is the son of attorney John Stanley Pottinger, a former official in the Nixon administration, who later had a lucrative banking career and later represented over 20 alleged victims of Jeffrey Epstein's sexual abuse.

Matthew Pottinger attended the University of Massachusetts at Amherst, where he took an interest in studying China and became fluent in Mandarin. He later became a reporter for Reuters and the Wall Street Journal, where he covered China. Matthew Pottinger recounted the harassment he endured while in China, including an incident where he was physically assaulted in Beijing by a “government goon.”

In 2005, Matthew Pottinger joined the Marines and served several tours as an intelligence officer in both Iraq and Afghanistan. While posted in Afghanistan in 2010, he met then-Lt. Gen. Michael Flynn, who would serve in 2017 as the national security advisor. Together they wrote a report that lambasted intelligence failures by U.S. forces in the war.

Through Flynn, Matthew Pottinger joined the Trump administration in 2017 as an expert on China and East Asia. He has been described as the “architect” of the Trump administration’s approach to China, including Trump's trade war against Beijing in 2018 and labeling it a “revisionist power” in the administration’s first national security strategy.

Despite serving for most of Trump’s term in office, it is not clear how much of a direct relationship the two maintained. In 2018, Trump lashed out at the New York Times after Matthew Pottinger told reporters that a June 12 summit with North Korea leader Kim Jong Un would be "impossible" to move forward. Trump said the paraphrased comments came from someone who “doesn’t exist" and that the Times should not use "phony sources."

Matthew Pottinger’s relationship with the Trump administration came to an end on Jan. 7, 2021. He was joined by a coterie of White House officials, who were dismayed by the storming of the Capitol and Trump’s handling of the crisis.

In pre-recorded testimony to the Select Committee, Matthew Pottinger pointed to a tweet by Trump that suggested Vice President Mike Pence lacked the courage to not certify the 2020 presidential election.

"I read that tweet. And made a decision at that moment to resign," Matthew Pottinger told the committee. "That's where I knew that I was leaving that day, once I had read that tweet."

CBS News reporter Catherine Herridge cited sources this week that described Matthew Pottinger as a "very serious professional," a "straight shooter" and "someone with a lot of principle."

Matthew Pottinger is a distinguished visiting fellow at the Hoover Institution, a conservative think tank. He reportedly lives in Utah and is married with two children.