Fairfax shareholders gave “overwhelming” support for the multi-billion dollar merger.
The deal was possible after Australia relaxed its media ownership laws last year.
The new business will be called Nine, losing the well-known Fairfax name.
Fairfax chairman Nick Falloon said the change was expected to be implemented on 7 December, subject to court approval.
The deal wraps in Nine’s television network, one of the nation’s biggest, and Fairfax newspapers including The Sydney Morning Herald, Melbourne’s The Age and The Australian Financial Review.
It also includes Fairfax’s many radio and digital assets, including news websites in other cities and property listings business Domain.
“Media consolidation provides significant potential by leveraging increased scale of audiences and marketing inventory to grow,” Mr Falloon said in a statement.
Until last year’s law changes, proprietors had been prevented from owning newspapers, radio and TV stations in the same city – a rule designed to protect media diversity.
Fairfax, which was founded in 1841, has struggled financially in recent years due to declining revenues.
Many current and former Fairfax employees had previously expressed sadness about the deal, with some raising concerns about whether it would compromise future journalism.
Fairfax chief executive Greg Hywood said on Monday: “Although it is the end of an era for the Fairfax corporate identity – independence is indelibly at the heart of our newsrooms and carries on into the future through our journalists.”
