In a surprise move, Fox will turn to AMC’s president, Charlie Collier, to take over its broadcast network in several months, the company announced Friday.

It had been widely assumed in Hollywood that Gary Newman, a co-chief executive of the Fox Television Group, would continue in the job. But Mr. Newman indicated to Fox that he would stay only through this television season, which ends in May. Lachlan Murdoch, who will be chief executive at the new Fox, did not want to wait that long to find a replacement.

Mr. Collier, a career cable man, has been president of AMC for a decade, and helped shepherd hits like “The Walking Dead,” “Breaking Bad” and “Better Call Saul.” His new title will be chief executive of entertainment at Fox.

It’s the latest change at a time of sweeping executive turnover for the broadcast networks. Leslie Moonves, the longtime head of CBS, was forced out last month after numerous allegations of sexual misconduct against him. On Thursday, Showtime’s chief executive, David Nevins, was named chief content officer of CBS, where he will oversee the network’s executives.