Riggleman was defeated in his bid for reelection in 2020, losing to Republican primary challenger Bob Good in a drive-through party convention.

[4] Riggleman had expressed interest in running for Governor in 2021 as an independent or third-party candidate, citing his belief that the Republican Party of Virginia is broken.

[14] In a phone interview with The Washington Post, he clarified that it was an "anthropological book sort of based on parody and satire" and said, "I thought it was funny.

[18] He is also one of the co-authors of the Network Contagion Research Institute (affiliated with Rutgers University) report called "THE QANON CONSPIRACY: Destroying Families, Dividing Communities, Undermining Democracy"[17] which he wrote before the January 6, 2021 storming of the US Capitol.

Since leaving Congress in January 2021, Riggleman has been working with experts and academics at the Network Contagion Research Institute to study disinformation and how to combat it.

[20] On September 26, 2019, Campbell County Supervisor Bob Good—who also worked as an athletics official at Liberty University—announced his intention to challenge Riggleman in the 2020 Republican primary.

In his announcement, Good accused Riggleman of "betraying" the trust of conservative voters in the 5th district along with casting votes that were not in his constituency's best interest.

Riggleman added "As we transition to a new administration I implore all to consider the sources of information you receive, to fact check diligently", he pleaded, asking his fellow Americans "to recognize that many bad actors who spread spurious and fantastical conspiracy theories under banners like QAnon, Kraken, 'Stop the Steal, 'Scamdemic' and many other emotive terms and coded language are not disseminating information rooted in knowledge but with questionable motives and greed.

"[25] On August 6, 2021, Riggleman was appointed to serve as a senior staffer to the United States House Select Committee on the January 6 Attack on the U.S.

[26][27] In April 2022, Riggleman sent the January 6 Committee chairman and vice chairwoman a letter informing them of his decision to leave his position in the coming weeks.

[29] On Friday, June 3, 2022, Politico reported that January 6 Committee staff director, and former CIA Inspector General, David Buckley said in an email to staff the previous day: "I want you to know that I am deeply disappointed in [Riggleman's] decision to discuss the Select Committee’s work on television"[29]..."in direct contravention to his employment agreement"[30][31][32][33] In October 2022, Riggleman joined Issue One's Council for Responsible Social Media project, which states its mission is to address the mental, civic, and public health impacts of social media in the United States.

The council is co-chaired by former House Democratic Caucus Leader Dick Gephardt and former Massachusetts Lieutenant Governor Kerry Healey.

[34] On August 4, 2024, Riggleman endorsed Kamala Harris for President, while criticizing Donald Trump’s role in the January 6 protest and his pursuit of "power, revenge, and retribution".