After months of behind-the-scenes negotiations, Nine will screen matches four days a week starting in 2018, in a deal worth "up to $925" million, the NRL said.
The NRL said it was the biggest deal in free-to-air TV history.
The number of live games on free-to-air TV will increase from the present two to four, with matches to be played during prime time on Thursday, Friday and Saturday, and on Sunday at 4pm.
NRL chief executive Dave Smith said the deal had secured the long term future of the game.'
"There will be more live and free rugby league on television and that is what the fans want," Smith said in a statement announcing the new deal.
"And we still have simulcast rights, pay TV, New Zealand and international television rights to be negotiated.
"So the future of the game is in great shape."
Channel Nine boss David Gyngell welcomed the news.
"This is a transformational outcome for supporters, rugby league and Nine,"he said.
"It will enable views to see the best of the NRL, live and free, four days a week, anywhere and on any device."
Under the new deal the second match in each State of Origin series will be played on a Sunday night as part of a stand alone weekend of representative football which will also feature Pacific Nation Tests.
The premiership will be played over 25 rounds, one less than the current model, while international rugby league will be given a new priority and played in a dedicated window after the NRL season.
"In other words, we are preserving Origin as a marquee event of the year while minimising disruption to the premiership," Smith said.
"This will not only improve player welfare but it will be fairer for the clubs and fans."
The NRL has also regained control of the premiership schedule from broadcasters.
"We will be able to schedule the best games when fans want to see them and ensure all clubs receive the coverage they deserve on free-to-air television," Smith said.
The news will come as a blow to Channel Seven and Channel Ten who had been in the running to secure at least part of the broadcasting rights.