Great Britain had not won a female diving medal at the Olympics in 64 years before Saturday. They now have two in five days.
This pair came in highly-regarded, as medallists at the last two World Championships.
Toulson, from Huddersfield, is competing at her third Olympics aged just 24.
Spendolini-Sirieix, born in London to her Italian mother and French father – the star of TV show First Dates, was national champion at 15 and competed at the last Olympics a week before receiving her GCSE results.
After a solid start, a poor third dive looked to have knocked their medal chances but with one to go they were in fourth with the Canadian’s 4.44 points ahead.
The British pair had the advantage of diving first throughout and put in their best effort of the competition to apply the pressure.
A score of 77.76 did just that and the Canadian duo faltered slightly, scoring 68.16 with their final dive, to finish four points back on 299.22.
Chen Yuxi and Quan Hongchan, the overwhelming favourites as three-time reigning world champions, were again superb in sealing gold, as they kept up China’s run of having won this event every time it has been contested, since Sydney in 2000.
Behind them, North Korean pair Jo Jin Mi and Kim Mi Rae secured their nation’s second medal of the Games.