[1] Massie is known for his advocacy of limited government, fiscal responsibility, and individual liberties, often aligning with libertarian principles in his voting record.

[12] In 1993, Massie and his wife founded a company, SensAble Devices Inc., that allowed users to feel digital objects that appeared on a screen.

[14] In 1996, Massie completed a Master of Science degree (SM) with his thesis, "Initial haptic explorations with the phantom: virtual touch through point interaction".

[32] On May 22, 2012, Massie won the Republican nomination, beating his closest opponents, State Representative Alecia Webb-Edgington and Boone County Judge Executive Gary Moore, by a double-digit margin.

[33][36] Massie resigned as Lewis County Judge-Executive effective July 1, 2012, to focus on his campaign for Congress and allow an election to be immediately held in order to replace him.

[45] Massie broke from the majority of his party by opposing the reelection of Speaker of the House John Boehner, instead casting his vote for Justin Amash of Michigan.

[56] In July 2017, Massie joined Representatives Amash and John Duncan Jr., and Senators Rand Paul and Bernie Sanders in opposing a bill to impose new economic sanctions against Russia, Iran, and North Korea.

[63] In 2019, Massie signed a letter to Trump led by Representative Ro Khanna and Senator Rand Paul asserting that it was "long past time to rein in the use of force that goes beyond congressional authorization" and that they hoped this would "serve as a model for ending hostilities in the future – in particular, as you and your administration seek a political solution to our involvement in Afghanistan.

They asserted that the "Saudi-led coalition's imposition of an air-land-and-sea blockade as part of its war against Yemen's Houthis has continued to prevent the unimpeded distribution of these vital commodities, contributing to the suffering and death of vast numbers of civilians throughout the country" and that Trump's approval of the resolution through his signing would give a "powerful signal to the Saudi-led coalition to bring the four-year-old war to a close".

[70][71] In November 2019, he was the sole "no" vote in Congress on the Hong Kong Human Rights and Democracy Act of 2019, which he called an "escalation" with the People's Republic of China.

[80] On April 16, 2024, he co-sponsored a motion to vacate filed by Marjorie Taylor Greene in an attempt to oust House speaker Mike Johnson.

[85][86] After Massie's unsuccessful push, Trump said Massie should be removed from the Republican Party, calling him a "third rate [g]randstander"; John Kerry quipped that he "tested positive for being an asshole"; Representative Sean Patrick Maloney tweeted, "@RepThomasMassie is indeed a dumbass"; Representative Dean Phillips called his actions a "principled but terribly misguided stunt".

[87] In a phone interview with Betsy Woodruff Swan of Politico, Massie responded in jest to Trump's calls for his removal, stating "I take great offense to that.

He also questioned why people such as grocery store employees or truck drivers should be expected to work during the pandemic, but not members of Congress, who "make $174,000 a year" and have "the best health care in the world".

As of January 2023[update], Massie has only voted with Biden's stated position on two bills: H.R.256 (To repeal the Authorization for Use of Military Force Against Iraq Resolution of 2002), and the first introduction of H.R.3967 (the Honoring our PACT Act of 2022).

He supported legislation in 2019 to repeal the Authorization for Use of Military Force of 2001, arguing that it is too broad and that Congress should reclaim its constitutional right to declare war.

[98] He also supported efforts to withdraw U.S. forces from Iraq and Afghanistan,[99][100][101] and introduced a bill in 2019 to clarify that no authority exists for military action against Iran.

[75] Massie joined eight Democratic representatives in 2021 in voting against $1 billion in funding for Israel's Iron Dome air defense system, saying that he opposed all foreign aid out of concern about the national debt.

[109] In May 2024, AIPAC and allied groups announced a $300,000 ad campaign targeting Massie for perceived "anti-Israel views" while not officially endorsing any primary challenger.

[122] In 2013, he implied that cold weather undercut the argument for climate change, tweeting, "Today's Science Committee Hearing on Global Warming canceled due to snow".

[123] During a 2019 House Oversight Committee hearing on the impact of climate change, Massie suggested that concerns over rising carbon dioxide levels were exaggerated.

He added, "Banks, churches, sports stadiums, and many of my colleagues in Congress are protected with firearms, yet children inside the classroom are too frequently left vulnerable.

[160][161] In 2014, Massie joined Representatives Walter B. Jones and Stephen Lynch at a press conference to call for release of the 28 redacted pages of the Joint Inquiry into Intelligence Community Activities before and after the Terrorist Attacks of September 11, 2001.

[184] In October 2019, Massie criticized the jail sentence for Maria Butina, a Russian citizen who pleaded guilty to conspiring to act as a foreign agent in the United States.

[122] Massie is a part of a small group of Republicans who voted against a House resolution reaffirming commitment to the orderly and peaceful transfer of power in the United States under democratic principles.

[191] In June 2021, Massie was one of 21 House Republicans to vote against a resolution to give the Congressional Gold Medal to police officers who defended the U.S. Capitol on January 6.

"[194] On June 27, 2021, Massie said he and Representatives Marjorie Taylor Greene and Ralph Norman were suing Speaker Nancy Pelosi after they were fined for refusing to wear masks on the House floor.

[195][196] Massie endorsed Florida Governor Ron DeSantis for president in the 2024 election, saying that "America needs a leader who is decisive, respects the Constitution, understands policy, puts family first, and leads by inspiring".

[200] Massie released a statement in 2013 in which he called Roe v. Wade "one of the greatest judicial travesties of our time", then went on to say he believes life begins at conception.

[224] On December 4, 2021, Massie drew criticism for posting on his Twitter account a family Christmas photo with an assortment of guns, which happened to be several days after four teenagers had been killed in the 2021 Oxford High School shooting.