Total light vehicle sales amounted to 159,004 for the month, up from 149,301 and besting the previous record for August of 158,400 set in 2007.
"Building on strong sales over the year's first seven months, Canadian consumers drove the light vehicle market to its best August result ever," DesRosiers said in a report.
The record came as car sales jumped 7.2 per cent from a year ago to 70,836, while light truck sales climbed 5.9 per cent to 88,168.
For the year to date, sales totalled 1.2 million, up from 1.16 million at the same point last year.
Canada's Big Three automakers all reported increases in light vehicle retail sales for August as General Motors, Ford and Chrylser combined for a 4.7 per cent increase.
Import nameplates gained a combined total of 7.9 per cent.
Ford Canada said it sold 27,268 cars and trucks last month, while Chrysler put its light-vehicle sales at 21,932 for the month — both up seven per cent.
Meanwhile, General Motors said Chevrolet, Buick, GMC and Cadillac dealers delivered 21,091 vehicles in August, an increase of 0.1 per cent compared to last August.
Retail sales were up five per cent overall, as the Chevrolet Cruze posted a 16 per cent increase in sales for the month, Buick sales increased 18 per cent thanks to the Verano and the Buick Encore, and Cadillac sales increased by 54 per cent in August.
Chrysler said its sales figures mark the 45th consecutive month of growth year-over-year, as passenger car sales saw an increase of 20 per cent, with sales of 36,761 in the calendar year-to-date.
The Ford Fiesta saw sales climb 84 per cent year-over year, and Fusion had sales jump 57 per cent in August, led the increase for Ford.
The company also reported healthy increases for a number of other models, including the Ford Focus, Mustang and Taurus, up 16, 13 and 40 per cent respectively.
Several other auto makers reported their August sales figures Wednesday, with Honda logging combined sales of 16,208 vehicles by their Honda and Acura divisions in Canada, a 19 per cent increase over last year's sales.
Toyota sales were down slightly at 16,077 compared with 16,125 a year ago, while Lexus sales were up nearly 10 per cent at 1,570 compared with 1,431 in August 2012.
Nissan sales were up almost a third at 7,279 compared with 5,549. Infiniti sales totalled 913, up from 780 a year ago.
Subaru Canada also posted increases, marking six consecutive months of growth as it sold 3,339 units in August, a 24.6 per cent increase over the same period last year.
Kia Canada Inc., meanwhile, said it sold 7,502 cars and trucks in August, a decline of 2.3 per cent compared with the same month last year.