Recently arrived from Boroughmuir via a brief stint at Edinburgh Accies, Hamilton (pictured in action for the 2nd XV) was the star of the show at Neilson Park on Saturday.
He crossed twice in the opening 40 minutes, and once more after the break.
Former club captain Garry Cockburn also went over, while stand-off Gareth Pritchard added three conversions as the Reds recorded a much-needed four try, bonus point win.
Going into the match, Haddington were without full-back James Ferguson and brother Alex, both ruled out of contention through injury.
That meant Mark Robertson reverted to full-back, with Connor Munro again in the unfamiliar wing berth he occupied last week in defeat to Perthshire.
2nd XV captain Alex Watt retained his place on the replacements bench, where he joined Charlie Hamilton, Alex Cunningham and last week's 2nd XV hat-trick hero, Mark Renton.
Hamilton dived over after a pair of tap-and-go penalties, and completed his treble shortly before Cockburn went over after spotting a gap in the Orkney defence.
Cockburn's drive for the Orkney line came after good work by replacement Alex Cunningham, before Hamilton moved the ball wide to the prop, who barged over.
The hosts didn't get it all their own way, though, and Thomas was quick to acknowledge the Orkney side for their efforts.
They fell just short of securing a fourth try, but returned home with a losing bonus for finishing within seven points of their hosts.
Thomas' side moved up to third after another five-point win, but they will face a tough test this weekend when they take on the unbeaten GHK.

Haddington: Mark Robertson, Kyle Adams, Kyle Hamilton, Liam Clutton, Connor Munro, Gareth Pritchard, Jack Hamilton; Alan Laidlaw, Colin Stuart CAPTAIN, Garry Cockburn, Ben Laing, Harry Hamilton, Jonny Riddell, Kris Paterson, Kyle McGarvie
Replacements: Alex Cunningham, Charlie Hamilton, Mark Renton and Eck Watt