But the network is a frequent target of Mr. Trump and his allies, and its journalists have faced threats of physical violence, including a pipe bomb mailed to its Manhattan headquarters last year.

Frank Sesno, a former CNN White House correspondent who now works as the director of George Washington University’s School of Media and Public Affairs, said that there had long been a “revolving door” between politics and news outlets. But political aides typically have a “cooling-off period” between jobs and Ms. Isgur’s quick transition is unusual, he added.

He said CNN should clarify what Ms. Isgur’s role would be. “It’s one thing if you have somebody on staff whom you can consult, and it’s another thing if they are editing your copy,” he said. “Pretty big difference.”

CNN declined to comment on Wednesday. The memo from Mr. Feist said that Ms. Isgur would help “organize and communicate between news gathering, digital and television” arms of the network, which has a sprawling news operation.

Ms. Isgur did not respond to an email and a phone request for comment.

Some prominent journalists have forged careers in news after working in politics, including George Stephanopoulos, who was hired as a contributing correspondent for ABC News in 1996 after serving as one of President Bill Clinton’s closest advisers.

His move from the Clinton White House to ABC News — initially as a partisan member of a Sunday political panel, who would also do some reporting — raised hackles inside and outside the network at the time. He has since risen to become the network’s chief anchor and a host of “Good Morning America.”

And the road from political strategist to political pundit is well traveled on both sides of the aisle.