News Corp. vet David Hill is in and David Lyle is out at National Geographic Channels U.S.

Hill will serve as chairman of the channels group. Nat Geo TV marketing exec Courteney Monroe (pictured) has also been upped to CEO of National Geographic Channels U.S., replacing Lyle.

The movement comes on the heels of Monday’s departure of Howard Owens as president of the division.

Monroe, who had been chief marketing officer for Nat Geo Channels U.S. since she joined the company 2012 from HBO, will oversee all domestic  National Geographic Channels (Nat Geo TV, Nat Geo Wild and Nat Geo Mundo), which are a joint venture of Fox Networks Group and the National Geographic Society.

Hill is a longtime Rupert Murdoch ally who is senior exec VP of 21st Century Fox and a member of the Nat Geo Channels board of directors. Hill was most recently dispatched by the corporate office to Fox Broadcasting Co. to oversee the production of “American Idol” as the network underwent an exec shuffle in its alternative programming department. He’ll remain a Nat Geo board member and his role overseeing “Idol” even as he takes on the Nat Geo Channels chairman post.

The shakeup marks a major vote of confidence in Monroe by Fox Networks Group chairman-CEO Peter Rice and Nat Geo Society chief Gary Knell.

“Courteney is a truly remarkable executive, with a proven track record of energizing programming brands — both here at National Geographic Channels and during her time at HBO,” Rice and Knell said in a joint statement. “She is also a proven leader, who has a clear vision of the television landscape, and we are very lucky to have her overseeing our domestic channels.”

Nat Geo Channels are a big priority for Fox Networks Group because they have such broad international reach and a gold-plated brand. Although the channels have had some programming successes in recent years, sources said that Lyle and Owens at times clashed with execs on the Nat Geo Society side.

Nonetheless, Rice and Knell credited Lyle with revving up the ratings and revenue for the group with hits such as “Wicked Tuna” and “Brain Games.” On his watch Nat Geo made a successful foray into scripted programming with the telepics “Killing Lincoln” and “Killing Kennedy,” based on the novels by Bill O’Reilly (still to come later this year is “Killing Jesus”).

“David Lyle led National Geographic Channels U.S. through a period of tremendous commercial and creative growth, including the highest-rated period in the channel’s history,” said Rice and Knell said.

Lyle came to Nat Geo Channels in 2011 after heading the Fox Reality cabler, which was transformed into Nat Geo Wild.

Here’s the memo Lyle sent to Nat Geo Channels staffers Tuesday morning:

Dear Colleagues:

Today, the worst kept secret is over – I am taking my leave as CEO of National Geographic Channels. I am exhilarated but somewhat saddened also.

I’m exhilarated that NGC and NG WILD are in rude health with EBITDAs (profits) at all-time highs, and with programming featuring the most watched specials, series and year in the channels’ history. And I’m extra pleased that these successes have transferred to National Geographic Channels internationally.

But business and programming successes aside, I am thrilled that as a team we took the risks and introduced new genres of shows like drama, and even had a go at comedy. Over the last three years we have changed the face of the Channel by introducing contemporary entertainment to the proud 125 year tradition of authenticity.

On a personal level, I am also delighted to be returning to sunny LA. I will farewell the snowdome of Washington and the bubble inside the bubble. (There will be a giveaway of my hats, scarves, boots and gloves).

But I am saddened to say farewell to a great group of colleagues – people who toiled passionately to bring great shows to air. On the Christmas cards I thanked everybody personally…. and meant it. But I can’t do that here. But as they say on Idol… for those who remember Idol… it has been a journey, and of course the journey continues.

So good luck to us all, and to all a goodnight.

David Lyle