In hiring Ms. Brown, Facebook asked her to create partnership programs with news organizations that used the platform. A former prime-time anchor on CNN, Ms. Brown built a rapport with news executives who saw Facebook both as a rival for digital advertising dollars and as an important — but fickle — source of traffic for their websites and apps.

When she joined Facebook, the company had already begun courting the news industry with products to encourage publications to post their content on its platforms and weed out misinformation. Early efforts included Instant Articles, a program that allowed people to consume stories in Facebook’s app, and a third-party fact-checking program.

Ms. Brown’s hiring seemed to indicate that Facebook’s founder, Mark Zuckerberg, was putting a premium on high-quality news and information. She led the development and launch of Facebook News, a tab focused on news and lifestyle coverage, and Bulletin, a newsletter platform for marquee writers including the memoirist Mitch Albom, the magazine writer and podcaster Malcolm Gladwell and the Nobel laureate Malala Yousafzai.

But as Facebook began de-emphasizing news, Ms. Brown’s role shifted. Her remit expanded to include partnerships in sports media and entertainment, while the products she launched were left to languish. Last year, Facebook said it was shutting down Bulletin, and it stopped paying publishers for content that appeared in its news tab.