One of the NRLW's most electrifying stars, Upton has become the first big-name Knight to be unveiled as part of the 24-player squad for last year's premiers.
NRLW players were restricted to signing single-year deals until the start of this season, as the competition expanded and there was less financial certainty.
However the introduction of a women's collective bargaining agreement and set salary-cap figures for the next five years has significantly altered the outlook.
"Tamika is arguably the best player in the game and we are thrilled that she is the first player to sign on with the club for the long-term," Newcastle's football boss Peter Parr said.
"She will not be the last.
"Tamika brings supreme athletic ability and football smarts to our team. But she is far more than that.
"She is a leader, a great community contributor, and a wonderful role model."
The retention of 26-year-old Upton came after the Knights lost fellow marquee star Millie Boyle to the Sydney Roosters.
Cronulla also confirmed their first signing on Wednesday, with NSW State of Origin dummy-half Quincy Dodd joining the club from St George Illawarra.
Dodd played her junior football and state cup for Cronulla, and said it was a no-brainer to move to the Sharks when the club earned their maiden NRLW license for this year
"There were other offers from other clubs, but deep down I know I am a Sharky and I belong here," Dodd said.
"I have always been a Sharks fan, I live just around the corner.
"It's like a dream come true to play NRLW for the Sharks. Finally we're here, and it's going to be such a great time."
19°C