The 36-year-old, who moved to Edinburgh from South Shields for a training camp 16 years ago and never went back, took just 77 seconds to dispose of Helene Wezeu Dombeu of Cameroon in her gold medal match.
Clark revealed she had some doubts over whether she could lift herself one more time.
"All day has been pretty nervous, and on the back of what happened yesterday, with all the medals Scotland won in the judo, I guess there is that added pressure," she said.
"There were moments when I thought my body was not going to make it, even though you want to, and bits are falling off.
"They changed the rules recently, and that affected my judo, which put doubts in my head, but as I started getting fitter again, I made the decision I was going to compete, and if I was going to compete, then I was going to be as fit as possible, today I could not have felt better."
It completed her redemption from a serious ankle injury and a first round defeat at the London Olympics, and brought her career full circle following a silver medal in judo's last participation at the games, in Manchester 2002.
Her club mate Patrick Dawson wasn't so fortunate, however, his attempts to capture a bronze being defeated by Jake Bensted of Australia.
But further good news came when Sally Conway clinched Scotland's eighth judo medal of the games.
Her bronze was confirmed when she overcame India's Sunibala Huidrom of India in the -70kg category on countback of penalties in a contest with no scoring throws.