President-elect Donald Trump selected Rep. Elise Stefanik to be his U.S. ambassador to the United Nations, multiple Trump officials told ABC News.

"I am honored to nominate Chairwoman Elise Stefanik to serve in my Cabinet as U.S. Ambassador to the United Nations. Elise is an incredibly strong, tough, and smart America First fighter," Trump said in a statement to ABC News.

Stefanik, a Republican congresswoman from New York's 21st District, was elected last week to her sixth term in the House. Born in 1984, she was at the time of her 2014 election the youngest woman to ever win a seat in Congress.

She joined House leadership in May 2021, when she was elected as chair of the House Republican Conference. She replaced former Rep. Liz Cheney in the role after Cheney was denounced by her party for her criticism of Trump in the wake of Jan. 6.

Stefanik came to Congress as a relatively moderate Republican and skipped the 2016 Republican National Convention when Trump first became the party's presidential nominee.

But she became one of Trump's most vocal allies, denouncing his first impeachment in 2019 and later challenging the 2020 election results.

In the past year, she played a leading role in House Republicans' response to antisemitism on college campuses. She grilled university presidents on their handling of campus protests over the Israel-Hamas war, several of whom later stepped down from their roles.

Stefanik, a staunch supporter of Israel, has also repeatedly accused the United Nations of antisemitism. She has called for defunding the United Nations Relief and Works Agency for Palestine Refugees, the chief distributer of aid in Gaza, amid Israel's allegations that Hamas infiltrated the group.

Stefanik told the New York Post, which first reported developments of Trump's decision, that she was "truly honored to earn President Trump's nomination to serve in his Cabinet as U.S. Ambassador to the United Nations."

Stefanik said that when speaking with Trump, she "shared how deeply humbled I am to accept his nomination and that I look forward to earning the support of my colleagues in the United States Senate."

Control of the House remains in the balance as several key races have yet to be called, though Republicans are closing in on the number of seats they need to secure the majority.

Stefanik will have to vacate her seat to become ambassador, though she would not be confirmed for her new role until after the presidential inauguration at the earliest.

New York law mandates that Gov. Kathy Hochul set a special election date via proclamation for within 10 days of the seat's vacancy -- and the election date itself must occur no sooner than 70 but no more than 80 days from the date of proclamation.

Stefanik handedly won reelection last week, beating her Democratic challenger by 24 points. While the New York State Republican Party told ABC News they have "no comment on candidates at this stage," chairman Ed Cox said he was sure the seat would remain Republican.

"On behalf of the New York Republican Party, I congratulate Elise Stefanik and her team on this well-deserved honor and commend President Trump for making such a wise and thoughtful selection," Cox said, in part, in a statement.

ABC News' Alexandra Hutzler, Brittany Shepherd, Lauren Peller and Oren Oppenheim contributed to this report.