The 27-year-old Kiwi international has been rewarded for his outstanding form in 2016, adding a further three years to his existing contract.
“Everyone who knows me knows how much the Roosters mean to me,” Waerea-Hargreaves said.
“It’s an honor to wear the Roosters jersey and to represent our area, and I consider myself incredibly fortunate to know that I’ll continue to be part of the team we have here for at least the next four years."