David Lyle was CEO for just three years and his exit is part of an entire management shakeup and top executive overhaul at National Geographic's TV business.
Under David Lyle's tenure viewers in South Africa and Africa saw Nat Geo shows like Killing Lincoln, Brain Games, Wicked Tuna, Killing Kennedy, SEAL Team Six and the latest National Geographic Channel showcase series, Cosmos: A Spacetime Odyssey.
Courteney Monroe who has been the chief marketing officer for National Geographic Channels in the United States since January 2012 is taking over as new CEO from David Lyle.
Nat Geo is also announcing that David Hill - a member of the National Geographic Channels board of directors and who is a senior executive vice president of National Geographic shareholder 21st Century Fox - is adding the title of chairman of National Geographic Channels US.
What this means is that David Hill is again taking on a much more influential role at Nat Geo - which he basically ran for half a year before David Lyle was made CEO in 2011.
"I am taking my leave as CEO of National Geographic Channels," says David Lyle. "I am exhilarated but somewhat saddened also".
"Both Nat Geo WILD and National Geographic Channel have introduced great franchise series that stand them in good stead for the future," says David Lyle.
The majority of the programming of National Geographic Channels US are channeled through to the National Geographic Channel (DStv 181), Nat Geo WILD (DStv 182) and Nat Geo GOLD (StarSat 300) seen on MultiChoice's DStv and On Digital Media's StarSat satellite pay-TV platforms in South Africa.