News Corp hired Miller, a former AOL chief executive, in 2009 to help revamp the company's digital strategy, with a particular focus on moving away from stand-alone web properties to digital content distribution. His duties included leading the company's efforts to resuscitate the pioneering social network MySpace as it lost market share to Facebook.

In 2013, News Corp plans to split into two separate companies, and it has been shuffling executives in preparation for that move. Newspaper, book and magazine publishing will comprise one company and the Fox television and film properties will be the chief components of the other one.

More big media companies are seeing the distinct role of a Chief Digital Officer as redundant, since digital distribution and consumption of media is beginning to take a larger integrated share of their day-to-day business with services like Netflix Inc and devices like the iPad.

The highest profile projects Miller had to oversee were rescuing MySpace, Murdoch's ill-fated social networking acquisition; the launch of digital magazine The Daily; and News Corp's partnership in video service Hulu.

Despite Miller's efforts, including the appointment of a high profile executive team to oversee MySpace, the social network, which Murdoch paid $580 million for in 2005, lost out to Facebook for users. After several quarters of significant losses it was sold for just $35 million in June 2011.

The Daily, which was launched in February 2011, was seen as Murdoch's risky bet that he could reinvigorate his news business with tablet devices like Apple Inc's iPad. But last month The Daily let go 50 employees, nearly a third of its total as it streamlines production to focus on its most popular features. News Corp has said it remains committed to the publication.

News Corp's stake in Hulu, a joint venture with Walt Disney Co, Comcast Corp and Providence Equity Partners is more often seen as something of a success but has also faced challenges regarding its future in particular as a standalone business.

More recently Miller has been involved in helping News Corp take stakes in video streaming device maker Roku and Bona Film Group.

Miller is leaving his post at the end of September and will serve as an outside adviser to the company on digital issues through fall 2013.

Former Yahoo interim chief executive Ross Levinsohn described Miller as "world class". Levinsohn co-founded a venture firm with Miller six years ago. Earlier this summer Miller declined to stand against his friend in the running for the permanent top job at Yahoo before Marissa Meyer was appointed as CEO last month.

News Corp said in June it is splitting into two distinct publicly traded entertainment and publishing companies in 2013. As part of the move, the company has been going through a sequence of top executive moves including the promotion of Peter Rice to oversee the Fox Networks Group.

(Reporting By Yinka Adegoke; additional reporting by Peter Lauria)

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