The team finished first in the men’s lightweight four final on Thursday afternoon.
The South Africans started conservatively, going through the 500 metres mark in third place, and dropped back to fourth by the 1,500m mark.
Over the last 500m stretch, however, they fought back and passed hosts Great Britain, Australia and Denmark to clinch gold in six minutes, 02.84 seconds (6:02.84).
Britain secured silver, 0.25 seconds behind the SA quartet, with Denmark bagging bronze a further 0.07 seconds behind.
The SA rowing team’s medal adds to golds secured earlier in the week by swimmers Cameron van der Burgh and Chad le Clos.
Le Clos continued his fine form in the pool when he posted the fastest semi-final qualifying time in the men’s 100m butterfly heats at the Olympic Games on Thursday morning.
Le Clos won his heat in 51.54 seconds, placing him in pole position for Thursday night’s semi-finals.
The 20-year-old South African, who won gold in the men’s 200m butterfly on Tuesday, withdrew from the 100m individual medley final, which will be held later Thursday, in order to focus on the butterfly, his specialty stroke.
American Michael Phelps, the silver medallist behind Le Clos in the 200m final, was second fastest of the qualifiers in the 100m heats in 51.72.
Meanwhile, Three-time Olympic medallist Roland Schoeman and countryman Gideon Louw both qualified for the men’s 50m freestyle semi-finals.
Schoeman, who secured the bronze medal in the same event at the Athens Games in 2004, won his heat in 21.92 seconds, qualifying fifth fastest for the semi-finals, while Louw was 11th fastest in a time of 22:12.
Karin Prinsloo also progressed to Thursday night’s semi-finals, finishing fifth in her women’s 200m backstroke heat and qualifying 13th fastest in two minutes, 10.34 seconds (2:10.34).