Mockridge has been chief executive of the company since July 2011, replacing Rebekah Brooks after she resigned as a result of the phone-hacking scandal.
"For nearly 22 years it has been my pleasure to have Tom Mockridge as a colleague," said News Corporation chairman and CEO Rupert Murdoch in a statement.
"Whether it was his early days with our newspaper group in Australia, his incredible work building Sky Italia, or his steadfast leadership of News International, Tom has always been a skilled executive and a trusted friend.
Mockridge - a previous chief executive of Sky Italia - was rumoured to be stepping down amid reports that he had been passed over for a new executive's position during restructuring of News Corporation.
The Wall Street Journal reports that its managing editor Robert Thomson is instead likely to be named chief executive of its new publishing division, as News Corporation prepares to separate its entertainment interests from its publishing companies.