A former governor of SC who is the daughter of Indian immigrants, Haley is the highest profile woman in Trump's Cabinet and is often seen as a possible presidential candidate. She was re-elected in 2014.
"It was a blessing to go into the United Nations with body armour every day and defend America", Haley, seated next to Trump in the Oval Office, told reporters.
Haley also praised the effectiveness of Trump's foreign policy efforts, which have drawn widespread criticism.
Haley said she and Trump together had "solved a lot of problems".
Sen. Bob Menendez (D-N.J.), the ranking member on Foreign Relations, thanked Haley in a statement "for her willingness to express moral clarity to the world and to President Trump, and promote American values and leadership on the global stage, even when she lacked the backing of the White House or State Department".
Haley's personal finances are detailed in her public financial disclosure as the USA ambassador to the United Nations.
Haley claimed exceptions due to personal relationships with the jet owners. According to Swan, Haley told Trump she wanted to resign during a conversation with him last week. How about (1) she is not qualified and (2) we are or should aspire to be a democracy, and not a monarchy or a House of Cards-like tv show?
Speaking to reporters in the Oval office, Trump said Haley would leave the administration "at the end of the year", adding that she had done an incredible job.
Trump said Haley would help select her replacement, and called her a "great friend" who did a "fantastic job".
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Prior to dedicating her life to public service, Haley worked at her family business. "Jared is such a hidden genius that no one understands", she said.
Now that she's leaving the high profile post, rumors are swirling over her successor.
AMs Haley told the press that her time at the United Nations had been "the honour of a lifetime", but that it was important for government officials to know when the right time was to leave.
Trump said that Haley told him six months ago about her plans to take time off after serving as ambassador for a year or two.
She listed hawkish policies to pressure Iran and the Palestinians, and the ground-breaking diplomatic outreach to communist North Korea.
Axios first reported this news. Haley enjoys strong support among Republicans and has always been rumored to harbor future presidential ambitions. At the White House, both Haley and the president praised her as a potent force behind the scenes.
Previously Haley was governor of the state of SC.
The daughter of immigrants from India, Mrs Haley was a frequent critic of Mr Trump during his election campaign.