CNN chief Jim Walton is quitting, saying the beleaguered news network needs a different leader with a new perspective and plans.

Walton built CNN into a profitable international news organization in his 10 years as boss. But the U.S. flagship network has suffered through some historically poor ratings in the past few months and is entrenched in third place behind rivals Fox News Channel and MSNBC in prime time. He announced his decision in an email to staff on Friday.

CNN historically suffers in the ratings during slow news periods, a fate Fox and MSNBC have minimized for themselves with partisan shows in prime time. Walton has resisted this approach, believing CNN's strength lies in being a nonpartisan news source.

He's 54 and has worked at CNN since 1981.