It was just their second victory of 2014, and the sixth by a Championship side over a Premiership outfit.
Their heroes were many but hooker James Parsons, tighthead Nic Mayhew, loosies Brandon Nansen and Leigh Thompson, and centre Matt Vaega stood out.
Canterbury were mostly flat and offered little but lateral attack after an opening burst.
At 52 minutes, Thompson broke free and looked to have bombed a try but eventually found replacement Niko Ratumaitavuki, who sliced through to score by the posts for a 15-point lead. Canterbury clawed back but it was all too late.
In the opening spell, Canterbury owned the first 10 minutes, and North Harbour the next 30.
Nathaniel Apa could not believe his luck after 20 seconds, while hooker Codie Taylor flopped over the line off a lineout drive for what may have been the easiest try of his life. That was it for Canterbury, barring a late Willi Heinz try, as the North Harbour pack gradually asserted itself and monopolised possession.
Thompson finished off a tremendous team try, then Tevita Li sprang to life, running a diagonal angle at top speed to score between the uprights after a nice inside flick by Matt McGahan. When Parsons followed up a Daniel Halangahu break to score by the posts, the home side had overturned a 14-0 deficit to lead by five. It could have been more if referee Paul Williams had not obstructed Bryn Hall when he was running a direct line to the posts.
It was all a far cry from Canterbury's 38-0 shellacking of North Harbour on this ground in 2013.
North Harbour has little time to come down off this high, hosting Hawke's Bay on Saturday night. Canterbury, with Dan Carter due back in the starting XV after his leg fracture, will be at home to Southland on Sunday afternoon.
North Harbour 29 (Leigh Thompson, Tevita Li, James Parsons, Niko Ratumaitavuki tries; Matt McGahan 3 con, pen), Canterbury 24 (Nathaniel Apa, Codie Taylor, Willi Heinz tries; Richie Mo'unga 3 con, pen). HT: 19-14.
- Campbell Burnes of the New Zealand Herald
