"Proud South Africans have crowded the streets as well as the internet, showing their support for our SA stars," Google said in a statement.
Le Clos snatched gold from United States swimmer Michael Phelps in the 200m butterfly final on July 31. On August 3 he won a silver medal, tying for second in the men's 100m butterfly in 51.44s.
Swimmer Cameron van der Burgh was the second-most searched South African Olympian, followed by runner Oscar Pistorius.
Van der Burgh won a gold medal in London on Sunday, July 29, for winning the 100m breaststroke in a world-record time of 58.46s.
Pistorius, a double-amputee, made history when he reached the 400m semi-final at the London Olympics on Sunday night.
In the last seven days Le Clos also led searches for the fastest-rising South African. He was followed by searches for Phelps and Olympic medals.
On the list of fastest-rising news searches in the past week, Le Clos took the first, second, and third positions.
Google said global mobile Olympic searches had increased 10-fold.
"Although Olympic searches grew substantially across computer, smartphones and tablets, mobile devices had the highest week-over-week growth, demonstrating their unique role as tools to keep us informed and connected."
In the past two days, South Africa made up 24 percent of Olympic-related searches on cellphones and tablets.