The Belgian won a highly entertaining match 9-11, 11-9, 11-4, 9-11, 11-5 after 76 minutes of high-quality squash in front of a packed gallery.
The score see-sawed throughout until Van den Herrewegen dominated the fifth game.
It was a fitting coincidence, since former club member Colin Payne spent two years based in Belgium as a professional.
Payne’s daughters Alice and Charlotte wore their late father’s Kent and England shirts for a poignant presentation ceremony.
Payne died in a tragic domestic incident in Dartford in November 2016.
His long-time friend and Kent team-mate Ben Ford from Bexley had been awarded a wild card entry into this world-ranking event.
Van den Herrewegen said: “It was a great match, very fair, and we were both trying to play the ball at every opportunity.
“This is a great tournament, it has a lovely feel to it with all the club members getting involved. They were hanging from the rafters upstairs.”
Soares, of Portugal, said: “I keep coming back and maybe one day I will this tournament. As Jan said, this is a great event with so many people working hard in the club to make it happen.”
Nick Wall, who was runner-up in the British Junior Open the week before, went out in the quarter-finals to MacGregor after suffering an ankle injury during the third game.
The 18-year-old said: “It was my ninth match in nine days and I didn’t want to risk doing any permanent damage.”
Before the final, Jasmine Hutton of Sussex won a pulsating Collins Jewel Women’s Challenge against Elise Lazarus of Essex 11-9, 13-11, 11-7.