The Kangaroos hadn't beaten Port since 2019, but proved far too strong at Marvel Stadium on Sunday, running out 17.11 (113) to 9.13 (67) winners.
Harry Sheezel gathered 31 possessions, Luke Davies-Uniacke's power around stoppages was telling, and Nick Larkey booted four goals in his first game as captain.
Port started well, with Darcy Byrne-Jones and Mitch Georgiades kicking the opening two goals of the game.
But the Roos were able to wrestle back control, with Larkey kicking his side's first goal and Cameron Zurhaar adding two more as North headed to quarter-time with an eight-point lead.
Jack Whitlock pegged a goal back for the visitors to start the second term, but it was one-way traffic after that.
With North tightening the screws defensively and moving the ball sharply from the back half, the Roos took full control.
A 55-metre bomb from Charlie Comben brought the home crowd to life, with Colby McKercher and Zane Duursma following up with quick goals before halftime.
The Kangaroos led by 25 points at the main break and carried their momentum into the second half, with Jy Simpkin soccering through a goal in the opening minute.
Larkey added two more for the quarter, with Luke Parker and Tom Powell getting in on the fun as North headed to three-quarter time with a 38-point lead.
The Power rallied to reduce the margin to 25 points early in the final term, but Paul Curtis settled the Roos' nerves with a clever snap after weaving through traffic, and North never looked threatened thereafter.
Jason Horne-Francis was met with a chorus of boos from the North Melbourne faithful all day, more than three years on from his decision to leave the Kangaroos after just one season.
It's the first time the 2021 No.1 draft pick has faced his old side in Melbourne since the 2022 trade.
Port's Zak Butters (23 possessions) and Connor Rozee (24) battled hard, but lacked support and were ultimately overwhelmed by North's midfield.
The Kangaroos will look to extend their winning form with matches against 2025 bottom-four sides West Coast and Essendon in the next fortnight.
