Technical looked to be a long shot when captain Andy Coburn failed a late fitness test, but top matches by Blair Scoullar and Aaron Burgess inspired coach Mike Fridge's side.
After playing most of the season in defence, Scoullar showed he still has an eye for goals.
His opener in the 14th minute was superbly taken.
Despite being ring-fenced by red shirts, he climbed high to loop a header into the top right corner of the goal, just above a despairing leap by centreback Tim Horner at the far post.
Technical continued to look the hungrier of the sides, and its reshuffled midfield, led by the effervescent George Milne, did not let Caversham settle.
However, a typical counter-attack by Caversham broke quickly up the right wing and a driven cross was headed past Technical goalkeeper Cam Burns by Robbie Deeley to square the match after 23 minutes.
Technical's Milne, Sam Enright and Riki Chidley battled to deliver ball forward, while Alistair Rickerby racked up miles as he broke from deep positions.
Deeley led the Caversham midfield effort, with Hamish Chang, Darren Overton and Blair Duncan trying to hook up with front-runners David Dugdale and Tom Jackson.
But under pressure, the classic Caversham passing game stuttered and opted for too many aerial balls, which Technical centrebacks Cam Parkin and Matt Joy easily cleared.
Joy had a particularly strong match, and added the icing to his performance when he restored Technical's lead with a booming header from set play to make the score 2-1 at half-time.
Caversham strung more passes together in the second half, but even some tailored lay-offs by Dugdale were ballooned over the crossbar from handy positions.
Meanwhile, Golden Boot winner Burgess showed his skills with penetrating runs, and one attempted overhead bicycle kick sailed narrowly wide.
Scoullar settled for a more direct approach and when the ball sat up knee-high in the 56th minute, he hammered a ferocious 20m volley past James Waggett's flailing arms.
Caversham continued to snatch at the trigger, spurning a couple of very good chances, and midway through the second half coach Steve Fleming gambled with a mass substitution of three players.
On came Tim Cook, Rhys Henderson and Alex McGregor with almost immediate results as Cook launched a header just over Technical's crossbar, and later had a close range shot cleared off the line.
But the maroon defence remained resolute, and it was Technical's young substitute, Michael Still, who sealed the match with a late run and accurate shot to clinch the title.
Fridge said a semifinal win in Christchurch last week had "sparked up" Technical for the final.
"Losing Andy [Coburn] was a blow, but as doors shut, others open, and our youngsters did the club proud with strong and skilful performances.
"Among many excellent performances, George Milne's industry and drive set standards in midfield. He was our man of the match."
Caversham coach Steve Fleming said Technical finished better than Caversham and deserved the title.
More young talent was on display in the curtain-raiser as unbeaten Mosgiel beat Waitaki Boys High School 2-0 with goals from Reuben Simpson to clinch the youth league.
