Former Trump adviser Peter Navarro reported to prison in Miami following a Monday order from the U.S. Supreme Court.
Navarro is attempting to appeal his contempt of Congress conviction, but the court refused to postpone his imprisonment until after the appeal is concluded.
Navarro will serve his full four-month sentence if his appeal is not successful before the end of that term.
"I will walk proudly in there to do my time," Navarro said during a press conference before turning himself in. "I will gather strength from this: Donald John Trump is the nominee."
DOJ RECOMMENDS 6 MONTH SENTENCE FOR FORMER TRUMP ADVISER PETER NAVARRO
Navarro was charged and convicted with contempt of Congress after he refused to comply with a congressional subpoena demanding his testimony and documents relating to the Jan. 6, 2021, attack on the U.S. Capitol.
Chief Justice John Roberts said he had "no basis to disagree" with the appeals court ruling that Navarro begin his sentence.
Navarro, who served as former President Trump's trade adviser, was the second Trump aide convicted of a misdemeanor contempt of Congress charge. Former White House adviser Steve Bannon previously received a four-month sentence but was allowed to stay free pending appeal by U.S. District Judge Carl Nichols, who was appointed by Trump.
Navarro said he could not cooperate with the committee investigating the Jan. 6 attack because Trump had invoked executive privilege, an argument that lower courts have rejected.
FORMER TRUMP ADVISER NAVARRO CONVICTED OF CONTEMPT AFTER DEFYING JAN. 6 SUBPOENA
"When I received that congressional subpoena, the second, I had an honest belief that the privilege had been invoked, and I was torn. Nobody in my position should be put in conflict between the legislative branch and the executive branch. Is that the lesson of this entire proceeding? Get a letter and a lawyer? I think in a way it is," Navarro said in January.
"I am disappointed with a process where a jury convicted me, and I was unable to provide a defense, one of the most important elements of our justice system," he added.
The lower courts found that Navarro could not actually prove Trump had invoked executive privilege.
Fox News' Louis Casiano contributed to this report
