2010

Ellmers became involved in politics after the passage of the Patient Protection and Affordable Care Act, which she opposed. She became involved in local Republican politics and joined Americans for Prosperity, a free-market political advocacy group.^[8] She sought the Republican Party nomination for Congress in North Carolina's 2nd congressional district, which was then held by seven-term incumbent Bob Etheridge. She faced car dealer Todd Gailas and retired businessman Frank Deatrich in the May 4, 2010 Republican primary. She raised and spent more money than her opponents. She won the Republican primary with 55% of the vote,^[8] winning every county in the district except Franklin.^[10][11]

In June, a physical altercation between U.S. Congressman Bob Etheridge and two young men claiming to be students working on a project^[12] was posted to the internet.^[13] The previously obscure Ellmers was highlighted by conservative blogs such as RedState and the National Review's The Corner.^[14] Donations increased markedly,^[15] and a SurveyUSA poll showed Ellmers ahead by one percent.^[16] Ellmers received an endorsement from former Governor of Alaska Sarah Palin on August 18 through Facebook, citing Ellmers' experience in the health care industry.^[17] Palin endorsed Ellmers along with three other women, on the 90th anniversary of women's suffrage in the United States.^[18]

On election day, November 2, 2010, Ellmers was declared the winner by the media and a recount conducted on November 17 and 18 confirmed that she defeated Bob Etheridge during the general election by a margin of 0.8% or 1,483 votes.^[19][20]

2012

The Republicans won control of the General Assembly in the 2010 election as well, and used the redistricting process to make the 2nd friendlier for Ellmers. They pushed the district well to the west to take in some heavily Republican territory between Raleigh and Greensboro. The two sections were connected by a narrow tendril sweeping from Fayetteville through Ellmers' home in Dunn to Raleigh. While Barack Obama won the old 2nd with 52 percent of the vote—one of the few majority-white districts in the south that went for Obama—John McCain would have carried the new 2nd with 57 percent of the vote.

Three Republicans decided to challenge her in the primary, but all of them were first-time candidates. She won the May 8 primary with 56% of the vote.^[21] In the November general election, Ellmers defeated Democratic nominee Steve Wilkins, a retired US Army officer and Moore County businessman, 56%–41%.^[22]

2014

Ellmers considered running for the U.S. Senate in 2014,^[23] but instead ran for re-election. In May 2014 primary she faced conservative Internet talk show host Frank Roche, who campaigned mainly against her support of immigration reform.^[24] Ellmers easily won the nomination, capturing 58% of the vote to Roche's 41%.^[25] "American Idol" runner-up Clay Aiken won the Democratic nomination after a close primary.^[26] Ellmers secured the seat again with a margin of 36,649 votes from Second District voters.^[27]

2016

A court-ordered redistricting made the 2nd significantly more compact. It lost much of its territory near Greensboro, and now took in a large chunk of the area represented by the former 13th district, forcing Ellmers into a primary challenge with George Holding, whose former district number was moved to the Triad area of North Carolina. Ellmers stated that Holding wasn't qualified to run in the district since he lived just outside its borders (though members of the House are only required to live in the state they represent). However, the new 2nd was geographically more Holding's district than Ellmers'.^[28] Ellmers had to contend with a high level of campaign spending by outside groups aligning themselves with the Tea Party movement, including Americans for Prosperity, which spent in the "low six figures" to defeat her.^[29] Conservative opposition to Ellmers arose from her push to prevent a vote on a 2015 abortion bill,^[29][30] from her votes on spending and budget bills, and from her vote in favor of the continuation of the Export-Import Bank.^[29] In the June 7th primary, she lost her primary campaign to Holding by an almost 30-point margin, coming in second by just 0.6% over third-place Greg Brannon.