"We could have sold more if we had more," Joe Hinrichs, Ford's president of the Americas, told a cheering crowd of workers at the plant.
With the production at Flat Rock, Ford will be able to make 350,000 Fusions each year. Hinrichs said the cars being made Thursday would likely be sold within two weeks, a much faster rate than the 60-day average for the industry.
The Flat Rock plant was built by Mazda Motor Co. in 1987 and became a joint venture with Ford in 1992. When Ford and Mazda severed ties in 2010, the fate of the Flat Rock plant was uncertain.
"This very location was on the chopping block. We didn't even know if it was going to stay open," said Jimmy Settles, the chief Ford negotiator for the United Auto Workers union.
During contract talks with the UAW in 2011, Ford agreed to bring Fusion production to Flat Rock. While Ford will have to pay U.S. workers more compared with Mexico, where workers make $2 to $3 an hour, the wage difference isn't as high as it once was.
In 2007, the UAW agreed that new hires could be paid at half the rate as veteran workers. All but around 150 of the 1,400 workers making the Fusion are new and make $15.78 per hour, the company said. That compares with an hourly wage of $28.50 for veteran workers at the same plant.
Hinrichs wouldn't comment on the profit Ford will make on the U.S.-built Fusions.
Ford isn't the only company that has moved work back to the U.S. because of the lower wage rates. General Motors Co. moved production of its Sonic subcompact to Michigan from South Korea in 2011.
Hinrichs said Ford has now hired 75 percent of the 12,000 hourly workers it promised to hire by 2015. Settles hinted that the company might even hire more to keep up with growing demand for new vehicles, but Hinrichs wouldn't confirm that.
"We're spending a lot of time on manufacturing planning," Hinrichs said. "Let's just keep growing our business and we'll take it from there."