In choosing South Dakota Gov. Kristi Noem as his homeland security secretary, President-elect Donald Trump is tapping a long-time loyalist to helm an agency that’s expected to play a central role in his immigration crackdown.

She will work closely with two immigration hardliners, incoming deputy chief of staff for policy Stephen Miller and administration “border czar” Tom Homan — both early choices that signaled Trump is serious about his pledge to conduct mass deportations.

Noem, 52, is a former state legislator and four-term congresswoman who was elected governor of South Dakota in 2018 and reelected in 2022. Her profile grew during the Covid-19 pandemic, when she rejected mask mandates and social distancing.

But she is perhaps best-known nationally for the controversy that followed the publication of an excerpt of her memoir earlier this year, in which she revealed she’d shot and killed a family dog, a 14-month-old wirehair pointer named Cricket, in a gravel pit because the dog was was “untrainable” and “dangerous to anyone she came in contact with.”

Facing backlash, Noem defended her actions, writing on X that her book had “more real, honest, and politically INcorrect stories that’ll have the media gasping.”

She also retracted a story in the book about a meeting with North Korean dictator Kim Jong Un, indicating that such a meeting never happened.

It was part of a round of unflattering stories that appeared to have ended any hopes that Noem, who tied for first choice in a February poll at the Conservative Political Action Conference in which attendees were asked who they’d like to see Trump pick as his running mate, would receive the vice presidential nod.

If Noem is confirmed by the Senate to lead the sprawling agency created under President George W. Bush in the wake of the September 11, 2001, terrorist attacks, she would be replaced in the South Dakota governor’s office by Lt. Gov. Larry Rhoden, a 65-year-old former state lawmaker, until the end of her current term in just over two years.

Noem attended Northern State University, but did not graduate, returning home to run her family’s farm in rural Hamlin County, South Dakota, in 1994 — the year her first of three children with her husband Byron was born.

After four years as a state lawmaker, Noem ousted Democratic Rep. Stephanie Herseth Sandlin in 2010. Eight years later, she defeated Attorney General Marty Jackley in a competitive Republican gubernatorial primary, and held off Democratic state Sen. Billie Sutton in the general election to win the governor’s office.

As governor, she resisted the lockdown measures that many other governors imposed during the coronavirus pandemic. She also aggressively courted Trump’s favor, including giving Trump a 4-foot replica with his face on Mount Rushmore when he visited the site for a Fourth of July fireworks celebration that Noem had pushed for in 2020.

Instead of running in the GOP primary herself, she endorsed Trump in 2023, lining up behind his successful bid to win his third consecutive Republican presidential nomination.

She has also taken several anti-immigration steps as governor. She opposed accepting Afghan refugees in 2021, and deployed South Dakota National Guard members to the US-Mexico border in Texas.

Noem established a political action committee early in the 2024 election cycle, and regularly traveled to events to back Trump. Seasoned veterans left her office, and she replaced them with more controversial aides, including former Trump 2016 campaign manager Corey Lewandowski.

She has also faced ethics complaints in South Dakota for inappropriately using her office to help her daughter with a real estate appraiser’s license. And more recently, she was banned by all nine indigenous tribes in her state from their lands over comments the governor made about tribal leaders focusing more on benefiting from drug cartels than their children.

Still, Noem has remained a staunch ally of Trump. In the closing weeks of the 2024 campaign, The Atlantic reported that Noem participated in a strategy briefing with Trump, questioning findings by campaign officials about the state of the race. And she moderated a memorable town hall in October when Trump swayed to music for more than 30 minutes.

Noem was among the Republicans with Trump on election night. She told CNN’s Erin Burnett the day after Trump’s victory that he “recognizes a lot of families during this campaign came to him and told him tragic stories of losing loved ones because of illegal immigrants that came in that were rapists or murderers or terrorists that are dangerous to this country. And he is focused on making their communities more safe.”

“President Trump is focused on dangerous people today. When I was visiting with him, he’s focused on making this country safer,” she said.

CNN’s Daniel Strauss, Alayna Treene, Kristen Holmes and Kit Maher contributed to this report.