Under the changes, News Ltd will streamline its editorial and sales operations at its newspapers, which include The Daily Telegraph, Herald Sun and The Australian.
Coinciding with the restructure announcement, Mr Williams confirmed News Ltd would buy Australian Independent Business Media, which publishes the Business Spectator website and Eureka Report.
Mr Williams did not say how much News paid for the business, but reports suggested it was more than $20 million.
Earlier, News Ltd announced it had made a $1.97 billion bid for James Packer's Consolidated Media.
The deal, if approved by regulators, will allow Rupert Murdoch's News Ltd to dominate Australia's pay TV industry.
News Ltd would take full control of Fox Sports and lift its stake in pay TV operator Foxtel from 25 to 50 per cent, making it a joint owner with Telstra.
Mr Williams said significant changes were needed to be made to the way News Ltd worked, managed and delivered its products.
"This is the only way to drive the company forward and respond sensibly and properly to the rapid change evident in the landscape of media operation and use," he said.
"We must change to create a viable and sustainable future.
"Frankly, the changes we are living through are economically challenging requiring a resilient approach and original solutions."
As part of the changes, News Ltd will adopt a single national approach to its operations.
It will manage the editorial operations at its metropolitan daily, Sunday and community newspapers across each state as a single network.
Its state-based sales teams will also be combined.
In line with its new national approach, News Ltd will cut its divisions along Australia's east coast from 19 to five.
News makes 80 per cent of its revenues in Queensland, NSW and Victoria.
News' digital operations, News Digital Media, will be also incorporated into the five new divisions.
Details of the News Ltd restructure follow moves by rival Fairfax Media to undertake its own major shake-up that will lead to 1900 job losses over three years.
The restructures are part of moves by the country's major media companies to streamline their print and digital operations.
-AAP
-AAP