Meet Nikki Haley, Trump's pick to be the ambassador to the United Nations

President-elect Donald Trump announced Wednesday that he plans to nominate South Carolina Gov. Nikki Haley as US ambassador to the United Nations, but the relationship between the two politicians hasn't always been genial.

Haley was thought of as a rising star within the Republican Party throughout the campaigning for the 2016 election.

Earlier this year, she delivered the rebuttal to President Barack Obama's final State of the Union address was widely hailed as a slam-dunk success. In the speech, she took a veiled shot at Trump by imploring Americans not to succumb to "the angriest voices."

"Today, we live in a time of threats like few others in recent memory," she said. "During anxious times, it can be tempting to follow the siren call of the angriest voices. We must resist that temptation."

Haley is the daughter of Indian immigrants and the first minority governor in South Carolina's history. Some accused Trump of stoking anti-immigrant rhetoric during his campaign for president.

Trump also went after Haley during the primaries. In March, when Haley was supporting Sen. Marco Rubio in the Republican primary, Trump tweeted: "The people of South Carolina are embarrassed by Nikki Haley!" She responded by tweeting, "Bless your heart," which is not exactly a nicety in the South.

Haley also made a possible reference to the campaign of Trump's general-election rival, Democratic presidential nominee Hillary Clinton, in September. She tweeted that she started her day with "Fight Song" by Rachel Platten, the same song Clinton blasts at nearly every public appearance she makes.

"Started my day with 'Fight Song' by Rachel Platten," Haley tweeted. "Wanted to share so that everyone gets an additional boost!"

Haley did support Trump once he became the Republican presidential nominee. And she has been mentioned as a possible future Republican presidential contender for a future election.

Haley first rose to national prominence when she decided to remove the Confederate battle flag from the South Carolina state-capitol grounds after Dylann Roof allegedly killed nine black Charleston churchgoers in June - a move that went against the grain of traditional Southern conservative politics.

"It came down to one simple thing," she told The New York Times at the time. "I couldn't look my son or daughter in the face and justify that flag flying anymore."

Of the decision to lower the flag, the Times wrote it "was a moment of political and racial drama, and a signature moment for Ms. Haley, who blended the traditional values of the South - faith, family, empathy - into a powerful call for taking down the flag as a gesture of unity, healing and renewal."

Haley has had a high approval rating in South Carolina in the past, but it fell to 48% in a Public Policy Polling survey from August. She's also fairly popular among Democrats.

She was first elected to the South Carolina State House in 2004 and just five years later was running for governor.

Haley's gubernatorial campaign was fairly rocky at times. Bloomberg Politics noted that one state lawmaker called her a "raghead," and that "campaign fliers compared a 'white male/Christian/business owner' to an 'Indian female/Buddhist/housekeeper.'"

She became the youngest governor in South Carolina history at just 38.

Allan Smith contributed to this report.