Mr. Pack, who is awaiting Senate confirmation, has collaborated on films with Mr. Bannon, a former head of Breitbart News, and has asserted that liberal political correctness is stifling the documentary film industry. If confirmed, he would hold considerable power. Recent legislation concentrates authority with the agency’s chief executive, and would replace its current bipartisan board with an advisory council.

The current top managers, appointed in the Obama administration and drawn largely from traditional media backgrounds, expect to lose their jobs if Mr. Pack comes in. They include the agency’s current chief executive, John Lansing, a journalist and former president of Scripps Networks, and Amanda Bennett, a Pulitzer Prize-winning investigative journalist who runs Voice of America. For now, though, they have intensified its efforts to encourage professionalism, reinforce ethical standards and remind staff of safeguards against political interference.

The agency’s work, and the episodes that suggested an ideological shift to the right from some staff members even before Mr. Trump’s team takes full control, have drawn particular scrutiny after signals from the president that he would like to see the government play a bigger role in developing a message separate from the news media.

In a Twitter post last month, Mr. Trump criticized the way CNN portrays the country and raised the possibility of the United States starting “our own Worldwide Network to show the World the way we really are, GREAT!”