Meanwhile, Sindh and Balochistan finished their respective campaigns winless after the completion of the tenth round fixtures.
Northern booked a berth in the final following an exhilarating contest against Khyber Pakhtunkhwa on the final day of the crucial first-class match at the UBL Sports Complex in Karachi on Thursday.
The Nauman Ali-led side managed to defend the modest 245-run target owing to a clinical bowling display allowing them to clinch a close win by 39 runs.
Nauman, the competition's leading wicket-taker, grabbed four scalps for 72 runs in 28 overs while Sadaf Hussain chipped in with a useful contribution to consign Khyber Pakhtunkhwa to their first loss.
An aggressive half-century from Israrullah threatened to take the game away from Northern but he perished to veteran left-arm paceman Sohail Tanvir.
Later, a stubborn stand between Zohaib Khan (51*) and Usman Shinwari (17) halted the opposition's victory charge as they inched closer to the target before Sadaf broke the partnership.
Zohaib then held onto one end firmly for the last wicket as Junaid Khan consumed 18 deliveries without scoring a run.
Ultimately, Junaid was dismissed by Faizan Riaz to spark celebrations from the Northern camp.
Khyber Pakhtunkhwa ended just six points short behind the second-placed Northern, who claimed all the 24 points on offer in the game.
Northern started the season as the underdogs and languished in the bottom half of the table for several rounds in the face of two defeats.
They will now meet Central Punjab in the final at the National Stadium Karachi from 27 to 31 December.
Central Punjab settled for a draw in their clash against Southern Punjab to confirm they ended the ten rounds at the No. 1 position.
Skipper Ahmed Shehzad and opening batsman Salman Butt piled on heaps of runs as they brought up their individual tons in Central Punjab's second innings.
Butt amassed an unbeaten 158 off 256 deliveries while Shehzad remained not out at 100 helping their side finish at 309-1 in 81 overs.
Southern Punjab's bowlers had to toil hard on a lifeless pitch with no luck as they could only take the wicket of Kamran Akmal (47) throughout the final day's play.
Central Punjab had claimed the early advantage in the game as they racked up 597-9 declared in the first innings with centuries from Shehzad, Usman Salahuddin, Mohammad Saad and debutant Abdullah Shafique.
Southern Punjab were helped by hefty contributions from Agha Salman (140) and Zeeshan Ashraf (141) but they were bundled out for 392.
The draw means Central Punjab collected 13 points and ended with a tally of 133 points.
Balochistan reached 181 for one in 26.2 overs in their second innings before the two captains shook hands to mark another draw in the tenth round.
Sindh's Fawad Alam slammed his fourth century of the season while Imran Butt strengthened his position as the leading run-scorer in the tournament thus far.
Butt was unbeaten on 101 at the close of play on the fourth day, taking his tally of runs to 934 in this year's Quaid-e-Azam Trophy.
Balochistan had earlier made 471-9 declared in their first innings courtesy of centuries from Akbar-ur-Rehman, skipper Imran Farhat and all-rounder Amad Butt.
Sindh were then able to achieve a 44-run lead owing to Fawad's stellar innings as Saud Shakeel top-scored with 151.
Despite acquiring one point more than their counterparts in the game, Balochistan's 84-point tally condemns them to last place in the six-team table.