Tom Hawkins was the Cat who almost stole victory for his team, kicking three consecutive goals in six minutes from the 16-minute mark of the final term to drag Geelong back into the contest.
The Cats piled on the last four goals of the match, getting to within six points at the 27-minute mark when Jimmy Bartel marked on the goal-line and converted from an acute angle.
The Roos frantically held on in the dying minutes, and ruckman Todd Goldstein was the hero.
After North skipper Andrew Swallow was pinged for a deliberate out of bounds with 32 seconds left on the clock, Andrew Mackie pumped the Cats deep inside their forward 50.
But Goldstein cut off the attack, flying in front of a pack of four players to take a game-saving mark 25m out from the Cats' goal.
North coach Brad Scott said he had felt helpless in the coach's box during the game's desperate last minutes, but felt his team had not done much wrong, paying tribute to the Cats' ability to fight back.
"We did a few things just technically wrong, but I think it would be wrong to say we took our foot off the pedal. I think they're a good team and they came at us," Scott said after the match
"Fortunately, we were good enough to withstand the charge."
The Roos coach said he felt his team had controlled most of the game after its fast start.
"We set ourselves to just get out and compete early and Geelong did what great teams do and they came back, but I thought for the first three-and-a-half quarters we were right on top," Scott said.
"We just played some really good footy, really good finals footy.
"The start was critical, but I just thought we continued that on for the majority of the game."
The Roos did not come out of the night unscathed, with Jamie Macmillan suffering a hamstring injury that saw him substituted from the match in the third quarter.
North, who finished the home and away season in sixth spot, became the first team outside the top four to reach a preliminary final since Collingwood in 2007 – and just the third since the existing finals system was introduced in 2000 (Hawthorn in 2001 was the other).
The Roos set their win up in the first term, kicking seven of the game's first nine goals to lead by 30 points at the 27-minute mark of the first term.
The Roos went into half time with a four-goal lead, but could not break the Cats despite stretching their lead to five goals on four occasions after the main break.
Goldstein was best on ground, taking full advantage of the Cats' undermanned ruck division by dominating Mark Blicavs and Josh Walker at ruck contests to give North's midfielders first use.
The Roos finished the game with 54 hit-outs, had 15 possessions and kicked one goal
, but it was his game-saving mark that will live longest in North fans' memories.
Vice-captain Drew Petrie was outstanding for North, kicking 4.4 and setting the tone with his defensive pressure that earned him two free kicks for forward-50 tackles.
Nick Dal Santo was all class with 35 possessions and a clinical finish from a tight angle for a goal at the 12-minute mark of the third term.
Sam Gibson put on a trademark running clinic, exploiting his elite endurance to rack up an equal game-high 35 disposals, 24 of which came in a rampant first half.
Geelong finished the home and away season in third and was the only top-five team North had not beaten this year entering September, with the Cats comfortably accounting for the Roos in rounds 10 (20 points) and 19 (32 points).
Cats coach Chris Scott said Geelong was not about to drop its bundle despite its straight-sets exit from the finals.
"I'm incredibly disappointed right at the moment, but really driven and motivated, even at this disappointing time, to improve and get better," Scott said.
"We were poor at times tonight. The opposition were excellent, but we found a way to get ourselves back into the contest and give ourselves a chance.
"And, as a club, we are incredibly proud of our players."
Hawkins finished with five goals for the match, after Nathan Grima had done a solid job on him for the first three quarters.
Selwood waged a one-man war against North at times in what was a spiteful clash, wearing strapping around his head for the much of the match and changing his torn jumper twice.
Josh Walker also proved a handy foil for Hawkins, kicking a career-best three goals.
North's win helped coach Brad Scott close the gap in his head-to-head battle with twin brother and Cats coach Chris, with the Roos now having won three of the teams' seven contests since Chris took over as Geelong's coach in 2011.
The Roos will enter next Friday night's clash with Swans at ANZ Stadium on the back of six straight wins and armed with the confidence of having won its only clash with the Swans this year, by 43 points at the SCG in round four.
The Cats join West Coast (2007) and Port Adelaide (2001) as the only top-four teams to bow out of the finals in straight sets since 2000.
The Roos could regain Lachlan Hansen (hip) and Leigh Adams (concussion) for the preliminary final against the Swans.