CNN Worldwide prexy Jim Walton announced Klein's exit and a new cabler structure in a memo to staffers on Friday morning.
Under the new settup, HLN's Ken Jautz will now run CNN U.S. as exec VP. Jautz's HLN has repped one of CNN's few success stories as of late, and even beats its bigger sister in some time periods.
"The reinvention of HLN is the latest in a string of successes he has led at CNN," Walton said.
Replacing Jautz at HLN will be Scot Safon, who will now serve as exec VP and run HLN.
"He is an innovator; HLN is an ideal news and information laboratory," Walton said.
Jautz was previously chief marketing officer of CNN Worldwide.
Walton said the company would also name an exec VP and managing editor of CNN Worldwide at a later date.
As for Klein, "Jon has made important contributions to the CNN story and he leaves with our respect and friendship, and with my sincere thanks."
Klein leaves on the eve of a CNN primetime launch that he helped construct, including the upcoming launch of "Parker Spitzer" and the January debut of Piers Morgan in Larry King's time slot.