The company spent over A$600 million developing and producing the car, being heavily based upon the ninth generation Mitsubishi Galant designed in the United States.

[1] The 380 continued Mitsubishi Australia's established habit of producing front-wheel drive sedans for the Australian market, and along with the Toyota Aurion, competed against traditionally well-established local rear-wheel drive Ford Falcon and GM Holden Commodore vehicles.

[2] After a slow sales start, the line-up was updated with the Series II in April 2006, with the entry-level model attracting a price discount of nearly 20 percent.

The development of the 380 began in 2002, when company executives in Japan gave approval to Mitsubishi Australia to commence work on two closely related vehicles.

The second, which was planned to be launched in 2007 was a long-wheelbase version known internally as PS41L to be produced in both left- and right-hand drive configurations.

[5] However, as Mitsubishi's financial woes worsened, and DaimlerChrysler pulled-out of the DaimlerChrysler-Mitsubishi alliance, PS41L was abandoned in 2004 and the likelihood of PS41 making it into production looked even more doubtful.

Company research conducted in mid-2004 revealed that 84 percent of Australians believed that Mitsubishi would cease production in Australia.

To reinstate consumer confidence in the brand, before the launch of the 380, a series of television commercials began airing in December 2004.

[6] Centralised around Mitsubishi Australia's then CEO Tom Phillips, the advertisements promoted the introduction of an industry-first five-year/130,000-kilometre (81,000 mi) warranty.

Mitsubishi reworked a slogan from former Chrysler chairman Lee Iacocca, concluding their commercials with the tagline, "if you can find a better-built, better-backed car anywhere, then buy it".

According to then CEO, Tom Phillips, the chosen name polled the best and, at the official launch, he stated "'380' conjured up images of high technology, European standards, sophistication and performance with consumers.

[9] From the very beginning of the project, Mitsubishi had always intended that the PS41 would be set apart from the North American Galant in terms of exterior styling.

The improved body stiffness resulted in better vehicle dynamics, which were also supported through the use of sophisticated suspension designs, new shock absorbers and stabiliser bars.

Mid-July 2007 saw the release of the 380 Series III, with range and price alterations designed to attract further sales and increase private buyer interest.

The price of the ES model rose by $1000 but was compensated for by the addition of alloy wheels, fog lights and traction control.

Next in the range, the auto-only SX adds sports seats with a unique grey trim, leather steering wheel, six-disc CD stereo with multifunction colour LCD display, sports rear bumper, 17-inch alloy wheels and sports-tuned suspension.

The Sports Edition, based on the ES, added 17-inch alloy wheels, high-profile rear wing, sports-tuned suspension, black interior trim and sunroof, for no extra cost.

In total, 15 units had already been assembled at TMR's Dandenong facilities with another five on the way from Adelaide for conversion, when Mitsubishi Motors Australia announced the end of local production.

[24] The last 380 sedan (a silver Platinum Limited Edition, body number 32044) left the production line on 27 March 2008.