In a 2016 op-ed in The Montana Standard, Knudsen expressed opposition to President Barack Obama's policy regarding allowing Syrian refugees to enter the United States.

"[8] Knudsen was unable to seek re-election to the House in 2018 due to term limits; he successfully sought election as Roosevelt County Attorney instead.

On September 5, 2023, special counsel Timothy Strauch filed 41 counts of prosecutorial misconduct against Knudsen with the Montana Office of Disciplinary Counsel, recommending "an adjudicatory panel from the commission be formed to hear the allegations and forward a recommendation to the Montana Supreme Court for possible disciplinary action.

"[14] On October 23, 2024 the Commission on Practice recommended to the Montana Supreme Court that Knudsen’s license to practice law be suspended for three months for actions committed by himself or by Department of Justice attorneys who he was supervising, finding that he undermined public trust in the legal system by refusing to comply with a Montana Supreme Court order and disparaging justices.

[15] On September 27, 2024 former Montana Highway Patrol Colonel Steve Lavin filed suit against Knudsen claiming that he had been coerced into resigning in March of 2024.