Toyota regained the global sales crown lost when the 2011 Japanese tsunami devastated its supplies as US rival General Motors saw its share of the global market shrink.
Toyota first overtook GM as the world's biggest carmaker in 2008, a position GM had held for 77 consecutive years.
A year later, GM was forced to restructure under bankruptcy protection and has shed a number of unprofitable brands.
While the largest US automaker is once again making record profits, its sales have been hit by a deep downturn in Europe, the reduction in its offerings and a decision not to chase market share with costly incentives and low-margin fleet sales.
GM said its share of the global auto market fell 0.4 points to 11.9 per cent in 2012 despite sales that grew 2.9 per cent to 9.2 million vehicles.
It has managed to hang onto the number two spot in worldwide sales, but German rival VW -- which aspires to be the world's biggest automaker by 2018 -- is not far behind with sales up 11 per cent in 2012 to 9.07 million.
Toyota maintains a much larger lead and has forecast its 2012 sales will jump 22 per cent to 9.7 million vehicles.
"Last year was a breakout year for us in a number of ways," said Jim Lentz, head of Toyota Motor Sales USA.
While it's great to be back on top again, Lentz insisted that "it's not that big of a deal."
"I don't really look at the global sales crown very much," he told AFP on the sidelines of the Detroit auto show.
"I'm sure we'll have a cup of coffee and say wasn't that great but by lunch we'll have forgotten about it and be back to business."
While Toyota also set new records for vehicle productions, sales and vehicle launches in the United States last year, Lentz said the key measure is how the company connects to customers.
"The important number is how we're doing with retail customers," Lentz said, noting that the Toyota brand was the number one US retailer in 2012 as sales grew 27 per cent.
The group's total US sales topped two million vehicles and captured 14.4 per cent of the US market, placing it in second place behind GM's fleet-fueled 17.9 per cent stake.
GM's international operations -- Asia-Pacific, Africa and the Middle East -- posted the biggest gains, with sales up 10.1 per cent at 3.6 million while its share was flat at 9.5 per cent.
Sales fell 8.2 per cent in Europe to 1.6 million vehicles, while GM's share narrowed by 0.2 points to 8.5 per cent, the biggest US automaker said in a statement.
North American sales rose 3.2 per cent to just over three million, though GM's share of its home market fell 1.5 points to 16.9 per cent.
Sales in South America shrank 1.9 per cent to just over a million vehicles, while GM's share of the region fell 0.8 points to 18 per cent.