WASHINGTON (AP) — President-elect Donald Trump has named Susie Wiles, the manager of his victorious campaign, as White House chief of staff, the first woman to serve in this influential role.

Wiles is widely praised inside and outside Trump’s inner circle for leading what was by far his most disciplined and well-executed campaign, and was seen as the leading contender for the position. She largely avoided the spotlight, even refusing to take the microphone to speak as Trump celebrated his victory early Wednesday morning.

Wiles’ appointment is Trump’s first major decision as president-elect and one that could be a defining test of his new administration as he must quickly build the team that will help run the massive federal government. Wiles brings no government experience to the role, but has a close relationship with the newly elected president.

She was able to do what few others have: help control Trump’s impulses—not by reprimanding him or lecturing him, but by earning his respect and showing him that he would be better off if he left her followed advice rather than ignoring it.

“Susie is tough, smart, innovative and universally admired and respected. Susie will continue to work tirelessly to Make America Great Again,” Trump said in a statement. “It is a well-deserved honor to have Susie as the first-ever female Chief of Staff in United States history. I have no doubt she will make our country proud.”

Trump went through four chiefs of staff — including one who served in an acting capacity for a year — during his first administration, part of his administration’s record-breaking turnover.

Successful chiefs of staff serve as confidantes to the president, helping to implement a president’s agenda and balance competing political and policy priorities. They also tend to act as a gatekeeper, helping to determine who the president spends his time with and speaks to — an effort that irked Trump in the White House.

The chief of staff is “absolutely critical to an effective White House,” says Chris Whipple, whose book “The Gatekeepers” describes how the role of the White House chief of staff shapes and defines a presidency. “In the end, the most important thing is to tell the president what he doesn’t want to hear.”

“On the positive side, she has shown that she can manage Trump, she can work with him and she can sometimes tell him hard truths, and that is very important,” Whipple said. “On the other hand, she really has no experience in the White House and hasn’t really worked in Washington in 40 years. And that is really a disadvantage.”

Wiles is a longtime Republican strategist who lived in Florida and managed Trump’s campaigns in the state in 2016 and 2020. Previously, she managed Rick Scott’s 2010 campaign for Florida governor and briefly managed former Utah Governor Jon Huntsman’s 2012 presidential campaign.

Chris LaCivita, who co-managed the campaign with Wiles, posted on X: “So happy and proud of one of the fiercest and most loyal fighters I have ever had the pleasure of working with!!!”

Trump often referred to Wiles during his campaign, publicly praising her leadership on what he was often told was his “best run campaign.”

‘She’s incredible. Unbelievable,” he said at a rally in Milwaukee earlier this month.

At a rally in Pennsylvania, where Trump made one of his final appearances before the election, he launched a profane and conspiracy-laden speech. Wiles was seen offstage and appeared to glare at him.

Later, at a meeting in Pittsburgh, Trump appeared to acknowledge his adviser’s efforts to keep him informed.

After complaining that men are no longer allowed to call a woman “beautiful,” he asked if he could delete that word from the record. “I can do that, can’t I, Susan Wiles?” he mused.