When Karoline Leavitt stepped up to the White House podium for the first time, the youngest press secretary in history pledged to follow her boss Donald Trump's "revolutionary media approach."

Less than a month later, the 27-year-old spokeswoman has certainly lived up to her promise — by picking one of the biggest fights between the U.S. presidency and journalists in decades.

Leavitt stunned the press corps when she announced on Tuesday that the White House itself — and not an independent association of correspondents — would henceforth choose which reporters get to cover Trump up close in the Oval Office and on Air Force One.

"The White House Correspondents' Association has long dictated which journalists get to ask questions of the President of the United States in these most intimate spaces. Not anymore," she said.

It was perhaps the most uncompromising performance yet by Leavitt, who appears comfortable whether she's explaining Trump's most outlandish talking points or exchanging jabs with reporters.

A Trump veteran who served as his 2024 campaign spokeswoman, Leavitt set the tone from her very first appearance in the James Brady briefing room on Jan. 29.

She accused the traditional media of "lies," unveiled a "new media" seat for podcasters, and opened up the White House to applications for press credentials in a drive that attracted more than 12,000 inquiries.

'Most Transparent'

Her subsequent performances have been equally confrontational.

Leavitt sometimes picks right-wing media outlets who ask pro-Trump questions, claiming that they had been excluded under Democrat Joe Biden's presidency.

Yet she has also given fluent answers to the "legacy media," even if she will often cut them off before they have the chance to ask a follow-up question — a long-established White House tradition.

Leavitt has also learned the first lesson of Trumpworld — never upstage your boss.

Trump, the consummate showman and former reality TV star, has spoken to reporters almost every day since returning to the White House.

Leavitt, in contrast, has only given a handful of briefings and is far more likely to pop up on conservative Fox News.

She insists that the Republican is the best person to explain his policies and has repeatedly described Trump as the "most transparent president in history."

But Leavitt has increasingly become the enforcer for what has now become a major battle over transparency and press access.

She was one of three White House officials named by the Associated Press in a lawsuit after the news agency was blocked from events because it refused to call the Gulf of Mexico the "Gulf of America," as a Trump executive order renamed it.

Leavitt strongly defended the decision to bar the AP, saying that the new name for the body of water was now a "fact" despite Mexico and other countries refuting it.

'Smart, Tough'

Trump said when he appointed Leavitt shortly after his election win in November that she was "smart, tough."

And Leavitt is nothing if not a Trump loyalist.

Raised in New Hampshire, where her family ran an ice cream shop, she sent a letter to her university newspaper in 2017 to protest against the fact that a professor had criticized Trump in class.

A veteran of the press office in his first term, she unsuccessfully ran for a seat in Congress in New Hampshire in 2022 on a pro-Trump, pro-gun ownership platform.

She then won his praise for steely television performances during his 2024 campaign.

On social media, Leavitt is a polished presence, mixing shots of life as a young working mother with clips of her on Fox News going after the "fake news" media.

Her loyalty was such that she returned to work four days after the birth of her first child when Trump survived an assassination attempt at a political rally last June.

"I looked at my husband and said, 'Looks like I'm going back to work,'" Leavitt told The Conservateur magazine in an article titled "Wonder Woman."