According to multiple sources, the president will bring Heather Nauert from her current position as State Department spokeswoman to replace Haley at the United Nations.
She had served as the State Department spokesman and was promoted in March to acting under secretary of state for Public Diplomacy and Public Affairs. Before this, she worked as an ABC News correspondent and as an anchor on the Fox News program, Fox and Friends.
Chris Murphy (D-CT) bashed Nauert as lacking in expertise, believing her to be the wrong choice for President Donald Trump's administration. Nauert beat out other contenders for the position including: former White House advisor Dina Powell, U.S. Ambassador to Canada Kelly Craft, and U.S. Ambassador to Germany Ric Grenell.
"I expect to continue to speak out from time to time on important public policy matters, but I will surely not be a candidate for any office in 2020", she said. Barred from traveling with Tillerson, she embarked on her own overseas trips, visiting Bangladesh and Myanmar previous year to see the plight of Rohingya Muslims, and then Israel after a planned stop in Syria was scrapped.
Nauert, who did not have a good relationship with Tillerson and had considered leaving the department, told associates at the time she was taken aback by the promotion offer and recommended a colleague for the job. She hadn't specialized in foreign policy or worldwide relations.
However Ms Haley has made no secret of the fact that she has had policy disagreements with Mr Trump.
The post is considered one of the highest profile positions in US diplomacy.