CNN Chief Jim Walton said Friday he is leaving the struggling cable network by the end of the year.

Walton joined CNN in 1981 and became president of CNN Worldwide 10 years ago, helping to build the network into a profitable news organization in the United States and internationally.

The ratings for the Atlanta-based cable channel have been suffering, however, with CNN's U.S. network reporting its worst-ever ratings for a second quarter. The network is now in third place behind bitter rival Fox News as well as MSNBC.

CNN has made multiple changes to its morning show and prime-time lineup in order to bring back and keep viewers

Walton made the announcement Friday morning in a note to staffers.

"CNN needs new thinking. That starts with a new leader who brings a different perspective, different experiences and a new plan, one who will build on our great foundation and will commit to seeing it through. And I'm ready for a change. I have interests to explore and I want to give myself time to do it," Walton wrote.

Walton said Turner Broadcasting Chief Executive Officer Phil Kent has asked him to stay through the end of the year.

"His vision has modernized and globalized our legacy news brand, enhanced CNN's journalistic standing, positioned it at the forefront of multi-platform branded news content and challenged the organization to think bigger, reach further and do better," Kent said in a statement.