[1] Only six days later, Rosendale ended his campaign after Donald Trump endorsed his opponent, Tim Sheehy in the Republican primary.

Rosendale worked in Maryland in the fields of real estate development and land management before moving with his family to Glendive, Montana, in 2002.

[15] During this legislative session, Rosendale was the primary sponsor of a resolution urging Congress to submit a balanced budget amendment to states.

[23] Rosendale ran for Montana State Auditor in 2016, when incumbent Monica Lindeen was ineligible for reelection due to term limits.

[26] In the general election, he faced Jesse Laslovich,[27] who was Lindeen's chief legal counsel and widely considered one of Montana's rising political stars.

[4] As state auditor, Rosendale approved direct primary care agreements[23] and authorized Medi-Share to operate in Montana.

In authorizing Medi-Share to operate in Montana, Rosendale determined that the company did not qualify as an insurer and had no obligation to pay subscribers' bills.

[34] In 2017, Rosendale proposed legislation that would create a reinsurance program so that individuals with preexisting conditions could access affordable health coverage.

[35] Rosendale condemned Bullock's veto, saying, "the governor has sacrificed good, bipartisan policy in favor of bad, partisan politics.

"[36] Rosendale then worked with a bipartisan group of Montana officials to create a reinsurance program and were granted a waiver to do so by the federal government.

[48] He also received early endorsements from elected officials around the country, including Senator Ted Cruz, Senator Rand Paul, House Republican Leader Kevin McCarthy, House Republican Whip Steve Scalise and Representative Jim Jordan,[49] as well as the endorsement of the Crow Tribe of Montana.

[53][54][55] Rosendale ran for reelection in the reconstituted second district,[56] which covers the eastern two-thirds of the state and includes Billings, Great Falls, and Helena.

[63] In June 2021, Rosendale was among 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.

[70][71] In September 2021, Rosendale was among 75 House Republicans to vote against the National Defense Authorization Act of 2022, which contains a provision that would require women to be drafted.

[74] In November 2021, Rosendale was one of six House Republicans to vote against the RENACER Act, which extended U.S. sanctions against Nicaragua and granted the president several ways to address acts of corruption and human rights violations by the Daniel Ortega administration, including the power to exclude Nicaragua from the Dominican Republic–Central America Free Trade Agreement (CAFTA-DR) and to obstruct multilateral loans to the country.

[78] On March 2, 2022, Rosendale was one of only three House members to vote against a resolution supporting the sovereignty of Ukraine in the face of the Russian invasion.

[83][84] On March 1, 2023, Rosendale posed for a photo in front of the United States Capitol with a former member of a white supremacist gang and a Nazi sympathizer.

[89] On March 19, 2024, Rosendale voted nay on House Resolution 149, which condemned the illegal abduction and forcible transfer of children from Ukraine to the Russian Federation.

[90] In 2017, Rosendale announced he would seek the Republican nomination to challenge two-term incumbent Democratic senator Jon Tester.

[92] In a competitive four-way primary, Rosendale faced district judge Russell Fagg, state senator Al Olszewski, and combat veteran Troy Downing.

Rosendale, who bought a $2 million ranch near Glendive when he moved to Montana in 2002, said he leased his land and helps run cattle on it.

Ron Kovach, a Rosendale spokesman, rejected the accusation as false and defamatory, and stated that Heitkamp would be the target of legal action.

[107][108] On March 8, 2024, Rosendale announced that he would also not run for reelection to his House seat, saying that "defamatory rumors" and alleged death threats had impeded his ability to serve.