Haley's influence at UN was blunted by Trump policy decisions that many other nations opposed, including recognizing Jerusalem as the Israeli capital, cutting aid to Palestinians and announcing a US withdrawal from the U.N. HR Council. She has also built a personal relationship with the Trump family.
Haley was appointed to the United Nations post in November 2016.
She gave no reason for her departure after two years, though there is speculation she will return to government or politics at some point. Some even speculated that she would soon run for president herself. A U.S. official speaking on condition of anonymity told The National that "no one had seen it coming in the White House", at least not four weeks before the midterm elections.
Haley stayed coy on her reasons for quitting, saying only that it was "important to understand when it's time to stand aside". She spoke out against racism and on issues of gender.
White House officials had sought to put a hold on record-setting administration turnover in the run-up to the November 6 elections, with aides being asked months ago to step down or commit to stay through Election Day to avoid adding to a sense of turmoil.
John Bolton. The current national security advisor had the title of USA ambassador to the United Nations once before.
Trump said "she has a very bright future and will be a key player wherever she goes".
"It has been an honor of a lifetime", Haley said of serving as United Nations ambassador.
"I don't see (my role) as pushing an "America First" policy, I see it as defending America because every day I feel like I put body armor on".
Nikki Haley resigns as United Nations ambassador
Israel's United Nations ambassador, Danny Danon, in a statement praised the outgoing ambassador: "Thank you, Nikki Haley! ". CREW reports that all three men donated to Haley's campaign when she was running for re-election to be governor of SC .
"She's done a fantastic job and we've done a fantastic job together", Trump said.
Trump called Haley a "very special" person, adding that she told him six months ago that she might want to take some time off. It came in response to an anonymous essay in The New York Times by a senior administration official that alleged there to be a secret "resistance" effort from the right in Trump's administration and that there were internal discussions of invoking the 25th amendment to remove Trump from office.
"I will support the president", Haley said. Trump tweeted that "The people of SC are embarrassed by Nikki Haley".
A former governor of SC who is the daughter of Indian immigrants, Haley is seen as a rising star in the Republican Party and a possible candidate in the 2020 presidential election. She was re-elected in 2014.
The daughter of immigrants from India, Haley favoured free markets and global trade and earned worldwide attention for speaking out against the Confederate battle flag in the aftermath of the 2015 massacre at a black church in Charleston, South Carolina.
South Carolina Republican Sen.
She is one of the most popular politicians in the United States, liked by her staff and has built a good rapport with global colleagues.
At the recent UN General Assembly session, Haley took the highly unusual step for a senior diplomat of joining street protesters against Venezuelan President Nicolas Maduro, shouting from a megaphone that the leftist leader should leave office.