Smith, 34, with team-mates James Roe, Naomi Riches, Pam Relph and cox Lily van den Broecke, won Paralympic gold in the mixed coxed four, to add to the world title they won in Bled, Slovenia last year.
He led the way as the number of GB victories eclipsed that of Super Saturday. They took six golds by early yesterday evening, bringing the nation's tally to 15 in four days.
The Eton Dorney victory marked a remarkable journey for Smith, who was born with a club foot but went on to represent his country in bobsleigh, karate and rowing.
Then, two years ago, doctors discovered a large tumour embedded in his spine and emergency surgery resulted in temporary paralysis.
He not only taught himself to walk again, but claimed a position on the GB rowing team after a competitive selection process.
Yesterday they stormed to victory, holding off world record holders Germany and Ukraine.
"The physio who found my tumours, Pat Dunleavy, he saved my life," said the rower from Aviemore.
"The tumours had been in there for 12 years and they recommended they take them out.
"I've now got a nice little scar in the front of my neck, I've got eight screws, two metal cages and a metal plate holding my neck in place and that was only two years ago.
"I was paralysed from the neck down and learning to walk again. I said at the start-line that nothing can be as hard as learning to walk again and waking up not being able to feel your legs.
"That's the hardest thing I have ever done in my life - but it's all worth it.
"We've worked hard all winter, we've done three sessions a day, seven days a week in all sorts of weather and we [effectively] won that medal in the winter.
"I can't remember the race – I've never pushed so hard in my life.
"When you thought you couldn't go any more, my body shut down in that last 250 and I just heard the crowd cheer us on and that made us raise our game."
Royal Mail said it was to celebrate Smith's Paralympics win by painting a red post-box gold in Aviemore.
Sports Minister Shona Robison said of the victory: "Congratulations to David Smith and all of the Mixed Adapative Coxed Fours team for their outstanding achievement in securing Paralympics GB's first rowing medal of the Games.
"It's fantastic that we now have another Scottish gold medallist at the London 2012 Paralympics and I'm sure we will have many more medal winners to come."
Anthony Kappes and Scots pilot Craig MacLean put aside the disappointment of mechanical failure in the tandem blind and visually impaired one-kilometre time trial to win GB's fifth cycling gold at the Velodrome. They beat team-mates Neil Fachie and Barney Storey to win the tandem sprint.
Aberdeen-born Fachie and pilot Storey had benefited from their rivals' mishap and won gold on Saturday but had to settle for silver yesterday.
MacLean, from Grantown-on-Spey, who won Olympic team sprint silver in Sydney in 2000, added: "It would've been nice to be celebrating the double, but I suppose we've redeemed ourselves a little bit. It's always nice to win. We know what each other can do," said Fachie. "We knew it would be the toughest race we'd have and on the day they were better than us."
Stef Reid leapt the furthest in the F42/44 long jump with a personal best but had to settle for a silver medal due to the vagaries of the points system for the combined-class event.
Four years ago, Reid would have won the gold in Beijing when the long jump was a straight F44 competition for single below-the-knee amputees
Ms Robison praised the 27-year-old – born to Scottish and English parents in New Zealand and raised in Canada – who switched allegiance to Britain two years ago.
"This is testament to years of hard work, training and dedication to her sport and another significant win for Paralympics GB," the minister said.
In the women's blind and visually impaired three-kilometres tandem pursuit, Glasgow-born Aileen McGlynn and pilot Helen Scott added a bronze medal to last week's 1km silver.
In the Olympics Stadium, 21-year-old Welshman Aled Davies took gold for Britain in the F42 discus final after winning bronze in the shot put.
Equestrian Sophie Christiansen, 24, from Berkshire, took gold in the individual dressage 1a grade with her horse Janeiro 6, Jessica-Jane Applegate took Britain's fifth gold medal of day four in the final women's 200m freestyle S14, and GB got a sixth gold in the mixed team dressage.
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