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.'