A South Newcastle junior, Fitzgibbon made his NRL debut late in the 2015 season.
The 23-year-old forward played five matches in 2016, before playing 14 matches and scoring eight tries in first grade this year.
“I have grown up in Newcastle and I love everything about the town,” Fitzgibbon said.
“I am starting to feel like I am playing some alright footy and hopefully over the next couple of years, I can play some more.”
There is no doubt Fitzgibbon deserves his two-year contract extension.
“Lachlan works hard on and off the field and that is important as we continue to build our squad for next season and beyond,” CEO Matt Gidley said this week.
“We look forward to seeing him in the red and blue for at least the next two years.”
With Fitzgibbon’s re-signing confirmed, the Club continues to build a strong squad for next season and beyond.
“We have a good, young core group that has been around the Club for a while now and hopefully starting to develop as a good team over next the few years and with the new recruits coming, it should put us in good stead,” Fitzgibbon added.
“I love playing for the Knights and I love the supporters…. they are probably the best in the comp, so I want to stay here as long as I can and I want the Club to be as successful as we can be.”