Since Ms. Sanders announced her resignation, White House officials have been discussing whether to reinstate the daily news briefing. Ms. Grisham declined to comment about issues of access, or the status of the briefing, and what remains a big question mark is how she will react when Mr. Trump does not want the news media in the room to document a photo-op.

In South Korea, Ms. Grisham was trying to prevent the North Koreans from overcrowding the room with their own reporters before American journalists could gain access, a White House official said. She and other White House officials worked as a team to control the situation.

And White House officials said it was too soon to draw any grand conclusions about what changes Ms. Grisham — who was seen as a combative defender of her former boss when she served as communications director for the first lady, Melania Trump — would seek to institute now that she occupies the dual role of White House communications director and press secretary.

She is expected to make some personnel changes, but so far, Ms. Grisham is still so new in the job that the official White House press secretary Twitter account held Ms. Sanders’s name until Monday afternoon. In the White House, Ms. Grisham has moved into her new office, but her name is not yet on the door.

Her first international scuffle harks back to her days as a media wrangler on the 2016 Trump presidential campaign, when Ms. Grisham was in charge of herding the traveling press corps from one location to another.

Ms. Grisham is not the first White House press secretary to get into a heated clash with foreign officials while traveling abroad. In 2010, Mr. Gibbs got into a shouting match with Indian security officials who tried to limit access for American journalists covering a photo opportunity between Mr. Obama and Manmohan Singh, the Indian prime minister at the time. Mr. Gibbs stuck his foot in the door and asked one Indian official if he was trying to break his foot, before threatening to pull Mr. Obama out of the meeting altogether. He won.

“It is the press secretary’s responsibility to fight, typically verbally, for press access,” said Ari Fleischer, who served as press secretary to President George W. Bush. “It’s rare that they have to go above and beyond and engage in physical action to preserve access. Robert Gibbs did it, and now Stephanie did it. It looked like it was natural and spontaneous, and good for her.”

Mr. Fleischer said he did not expect the “multiyear hostility” between Mr. Trump and the news media to dissipate. But, he said, “if she can carve out a role where on a personal level, she likes the press and the press likes her, it can go a long distance.”