The swift dismissal of Mr. Horowitz — without a public lawsuit or public pressure — represents a significant departure from how 21st Century Fox has handled other cases. 21st Century Fox, the media giant controlled by the Murdoch family, owns Fox Sports, Fox News and a number of other entertainment properties.

The development is yet another setback for a company that has been reeling for a year from a sexual harassment scandal at Fox News.

On July 6, 2016, the former Fox News anchor Gretchen Carlson filed suit against Roger Ailes, the former chairman of the network. That prompted an internal investigation that found several women at Fox News who reported misconduct. Mr. Ailes was forced out of the network, with a $40 million exit package, and the company went on to reach settlements with at least six women who accused Mr. Ailes of sexual harassment, according to a person briefed on the agreements. The company paid $20 million to settle the suit with Ms. Carlson.

Yet women inside Fox News said that issues of harassment and intimidation at the network went beyond Mr. Ailes. Current and former Fox News employees have said that they feared making complaints to network executives or the human resources department.

In late February, 21st Century Fox reached a settlement worth more than $2.5 million with Tamara Holder, a former Fox News contributor, who reported that she had been sexually assaulted by an executive at company headquarters. The network fired the executive.

Then in April, an investigation by The New York Times exposed financial settlements involving multiple women who had accused Bill O’Reilly of sexual harassment or other inappropriate behavior. After an internal investigation, Mr. O’Reilly was ousted on April 19. The cleanup continued in May, with the dismissal of one of the network’s presidents, Bill Shine, a protégé of Mr. Ailes.