Mr. Cohen will report to his predecessor, Robert Harper, who is vice chairman of News Corp.'s Twentieth Century Fox. He begins Jan. 14.
Mr. Cohen had been executive vice president of marketing, advertising and promotion for Walt Disney's ABC Entertainment Television Group, in charge of all creative and promotional advertising for all prime-time shows.
He was responsible for starting the network promotion "TV is Good," the so-called "yellow" campaign, which began in 1996. Previously, Mr. Cohen headed marketing at General Electric Co.'s NBC.
Twentieth Century Fox's announcement late Monday of Mr. Cohen's departure comes one day after Stu Bloomberg, co-chairman of ABC Entertainment, resigned.
Mr. Bloomberg will be replaced by Susan Lyne, who will have the title of president of ABC Entertainment and report to Lloyd Braun, now chairman of ABC Entertainment. Ms. Lyne had been executive vice president of movies and mini-series at ABC Entertainment.