A former F.B.I. agent who criticized the bureau in congressional testimony has been awarded back pay and had his security clearance reinstated, his lawyer said on Tuesday.

The former agent, Marcus Allen, resigned from the Federal Bureau of Investigation on Monday after reaching a settlement agreement, said his lawyer, Tristan Leavitt. Mr. Allen’s security clearance was reinstated on Friday after he appealed the agency’s decision to revoke it.

The F.B.I. notified Congress last year that it had revoked the security clearances of three agents who either took part in the Capitol attack on Jan. 6, 2021, or later expressed views about it that placed into question their “allegiance to the United States,” the bureau said in a letter to congressional investigators.

Mr. Allen was suspended in February 2022. He was awarded 27 months of back pay, Mr. Leavitt said.

Mr. Allen testified before the House Judiciary Committee last year and denied that he held “conspiratorial views” about Jan. 6 or sympathized with criminal conduct.

“I was not in Washington, D.C., on Jan. 6, played no part in the events of Jan. 6, and I condemn all criminal activity that occurred,” he testified. “Instead, it appears that I was retaliated against because I forwarded information to my superiors and others that questioned the official narrative of the events of Jan. 6.”

Mr. Leavitt called the reinstatement of Mr. Allen’s security clearance a “total vindication.”

“The F.B.I. has completely backed down and provided everything that we had asked for on behalf of Marcus,” Mr. Leavitt said in a statement.

In a statement, the F.B.I. denied any wrongdoing in the case.

“While we can’t comment on the specifics of any settlement, both parties agreed to resolve this matter without either admitting wrongdoing,” the bureau said, adding, “The F.B.I. takes seriously its responsibility to F.B.I. employees who make protected disclosures under whistle-blower regulations, and we are committed to ensuring they are protected from retaliation.”