ShedescribedJared Kushner, Trump's son-in-law and aide, as "such a hidden genius that no-one understands" for his work on renegotiating the NAFTA trade deal and preparing a long-awaited Middle East peace plan that has not yet been released. "It has been an honour of a lifetime".
She has been floated as a potential primary challenger to Trump in 2020, but she said Tuesday that she will not run and will be campaigning for Trump.
Trump said Haley first informed him of her decision to leave after two years in the post, saying she wants to "take a break".
But my sources point to yet another early favorite: Richard "Ric" Grenell, Trump's ambassador to Germany, whom I spoke with last week.
As a strong supporter of term limits, I have long believed that rotation in office benefits the public.
U.S. Permanent Representative to the UN, Ambassador Nikki Haley meets Israeli Prime Minister Benjamin Netanyahu at his office in Jerusalem, June 7, 2017.
Just four senators voted against UN Ambassador Nikki Haley when she was confirmed four years ago, and now the top Democrat on the Senate Foreign Relations Committee says he's "deeply concerned about the leadership vacuum she leaves and the national security impact of her departure at this time of continued disarray for this administration". "And I do think that sometimes it's good to rotate in other people who can put that same energy and power into it", Haley said.
"We've done a fantastic job together", he continued. He said he hoped she would come back to the administration in another capacity, adding,"You can have your pick".
"She's made it a very glamorous position", Mr Trump said.
Haley is a former governor of SC who has repeatedly deflected speculation that she might harbor presidential aspirations of her own. And no, she's not running in 2020. In April she announced new sanctions against Russian Federation but White House officials suggested they were premature. I saw that the media was trying to make it something disrespectful; that's not what it was.
The daughter of Indian immigrants, Haley alluded to Trump in denouncing "the siren call of the angriest voices" who disrespected America's immigrants. "She will continue to play a key role in our peace efforts and we will share more details on that in the future".
Ms Haley, 46, was made United Nations ambassador in January 2017, shortly after Mr Trump was inaugurated. "She challenged friend and foe to be better".
South Carolina Senator Lindsey Graham said she had been "a true agent of reform" at the UN.