The talented 15-year-old broke 60 at the course when he posted a 9-under-par 59 in the Otago intercollegiate final in March.
On Saturday, he finished with a 3-under total of 133 in the first trial for Otago representative honours.
Millbrook professional Ben Gallie grabbed the bragging rights over the amateur competitors, carding 65 and 63 for an 8-under-par 128, but was ineligible for the championship due to his professional status.
There was never a dull moment on his two cards as he recorded three eagles, nine birdies, five bogeys and a double bogey.
With several golfers missing due to Otago No 1 Brent McEwan's wedding, the event was always destined to be competitive, especially around the tight 4370m par-68 course.
Otago masters player Kyle Geary (Chisholm Park) posted a 3-under-par 65 to lead the field at lunch.
He held a one-shot lead over Jamie Anstiss and Mark Brooks (both Queenstown), while Logan was three shots off the pace with an even-par 68.
Geary and Brooks faded in the afternoon, each carding 73 to leave the tournament wide open for the chasing pack.
Logan fired a 3-under-par 65 which was enough to seal the title from Anstiss and Duncan Croudis (Otago), who closed with 68 and 66 respectively to tie for second on 134.
The fast-finishing Daniel Barnett (Queenstown) shot 65 to claim third on 135.
A highlight of the day was the effort of 68-year-old Arrowtown golfer Granville Joynes, who matched his age with a par round in a rare feat.
The attention now turns to this Sunday, when a full-strength field will compete in the Chisholm Park Open over two rounds.
- Michael Minty