The reigning Dally M medallist's 10-year contract is believed to be worth $11 million, putting the 23-year-old lock forward among the game's highest-paid players.
Taumalolo, who has won an NRL premiership has played 115 games with the Cowboys since his debut in 2010.
He has turned his back on pursuing a career in the NFL after trialling in front of scouts in the United States in the off-season.
"The NFL opportunity was pretty big for me. Obviously to throw myself into another game, the negatives outweighed the positives," said Taumalolo.
