David KlineThe turnstile for executives who have left Cablevision since late last year continued to spin with the news that David Kline has stepped down from his leadership position at Cablevision Media Sales.

Cablevision, the nation’s fifth-largest cable operator, has replaced Kline with former AT&T advertising executive Greg McCastle, who is now president of Cablevision Media Sales.

"Under David's leadership over the past 15 years, Cablevision Media Sales has delivered industry-leading advertising growth," said Tad Smith, president of Cablevision's Local Media Group. "In addition, he has been a pioneer in the evolving advertising landscape, creating products that provide advertisers with enhanced relevance and greater consumer engagement. He played a critical role in establishing Cablevision as an innovator of advanced advertising solutions, including addressable and interactive television advertising, as well as dedicated brand-specific channels. We thank David for his leadership and the contributions he has made to Cablevision over the years and know that he will succeed in his future endeavors."

Greg McCastleCablevision said Kline left the company to pursue other opportunities. He is the sixth executive to leave Cablevision since late last year. In November, Cablevision cable president John Bickham resigned, followed by COO Tom Rutledge’s resignation in December. A week later, Rutledge was named as Charter Communications’ new president and CEO.

Last week, executive vice president of corporate engineering and technology James Blackley and executive vice president of consumer operations Kathleen “Kip” Mayo handed in their resignations, while earlier in the month, Jonathan Hargis resigned from his position as Cablevision’s executive vice president of marketing and will leave the cable operator’s employ at the end of March.

McCastle served as senior vice president of AT&T Services and was a member of the senior leadership team of the AT&T Advertising Solutions organization.

At Cablevision, he will lead the company's advertising sales teams for Cablevision's local cable and advanced platform services; its local media properties, including News 12 Networks and Newsday Media Group; and the New York Interconnect.

He is also responsible for developing the company's sales strategy, as well as advanced multi-platform advertising solutions for national, regional and local advertisers, and he will report to Smith.

"Greg brings to Cablevision a disciplined approach to inventory management and a deep understanding of how data analytics and advanced advertising can maximize available media opportunities for clients across all platforms," Smith said. "He is a veteran of the telecommunications industry who has pioneered the development of targeted digital advertising, and we are very enthusiastic to have Greg join our team."

McCastle, who joined AT&T in 2008, was also the head of AT&T AdWorks, which included ad product marketing, ad product management and development, ad marketing and research, business development, and ad operations.

McCastle's previous experience included senior leadership roles in advertising sales with Westwood One, The Weather Channel, Sony International, and News Corp.'s News Digital Media and Fox Sports Net businesses. He currently serves on the board of directors of the Interactive Advertising Bureau (IAB), the Mobile Marketing Association, the Cabletelevision Advertising Bureau (CAB) and the Advertising Club of New York.