NEW YORK (CNN/Money) - AOL Time Warner said Tuesday it is replacing Jamie Kellner as the head of its television networks, naming CNN veteran Phil Kent as the new chairman and CEO of the Turner Broadcasting TV unit.

Kellner has overseen the networks for just under two years, and has been credited with helping the growth of The WB Network, the second-tier broadcast network that has had success attracting desired younger viewers. Kellner will remain chairman and CEO of The WB Network until his employment contract concludes next year.

Jamie Kellner is giving up the top spot at Turner Broadcasting, the networks unit of AOL Time Warner.

Kellner and other WB executives personally held an 11 percent stake in that network, although the Wall Street Journal reported that they sold the stake to AOL Time Warner last month for $128 million. Kellner's share from the sale was half of that, according to the New York Daily News.

"It's my intention to end my career at that point," Kellner, 55, said in a conference call with reporters, according to Reuters. "I don't want to be as involved as I have been and certainly not in setting up another business venture."

The move is effective March 10. Kellner sent a memo to employees saying that he had asked to leave in order to spend more time with his family in California. Turner Broadcasting is based in Atlanta.

Kellner is not the only top executive to leave the company recently. Last month Time Inc. veteran Walter Isaacson resigned as chairman of the cable news unit, 18 months after he took the top job at the news network. And Turner Broadcasting founder Ted Turner, the company's largest individual shareholder, said last month that he would give up the vice chairmanship, shortly after America Online co-founder Steve Case quit as chairman of parent company AOL Time Warner. Both those departures will take effect with the May shareholders' meeting.

AOL Time Warner's network group includes not only The WB but the cable networks, including CNN, TNT, TBS, Turner Classic Movies, and the Cartoon Network. It also includes the company's three professional sports teams, the Atlanta Braves, Hawks and Thrashers, which are reported up for sale as the company tries to reduce debt by selling non-core assets.

Networks is the second-largest profit generator, behind the company's cable operations, among the units of embattled media conglomerate AOL Time Warner. In 2002 Networks had EBITDA (earnings before interest, taxes, depreciation and amortization) of $2.03 billion, up 13 percent from 2001 results. Revenue rose 9 percent amid an improving television advertising market and viewership gains at The WB.

But the unit has also had its share of troubles. CNN has fallen behind competitor Fox News in average ratings, although it still gets a premium from advertisers as well as cable operator fees.

Last Thursday the company abruptly announced that it had called off discussions about possibly merging CNN with the news operations of Walt Disney Co. (DIS: up $0.57 to $17.30, Research, Estimates) unit ABC. AOL Time Warner Vice Chairman Ted Turner, the founder of CNN and Turner Broadcasting, had been critical of that proposed deal, most recently on CBS program "60 Minutes II."

The company issued a brief statement saying, "After careful review, it was determined that although there are great merits and possibilities to a merger of CNN and ABC news, the potential problems associated with the completion of such a transaction and the integration of these two distinct and great cultures was more than we want to pursue at this time

Kent is a former president and chief operating officer of CNN and had also headed up Turner Home Entertainment, which includes companies involved in home video, new media, licensing and merchandising, feature distribution and book publishing.

Shares of AOL Time Warner (AOL: up $0.56 to $11.07, Research, Estimates) rose 56 cents to $11.07 Tuesday. CNN/Money is also a unit of AOL Time Warner.