Mitsubishi's history goes all the way back to 1917, when the Mitsubishi Shipbuilding Company, Ltd., introduced Japan's first series-production automobile. The Model A was a hand-built seven-seat sedan based on Fiat's Tipo 3. It turned out to be too expensive, when compared to American and European mass-produced rivals, and was discontinued after only 22 cars had been produced, in 1921.

Thirteen years later, Mitsubishi Shipbuilding merged with Mitsubishi Aircraft, a company that had been formed in 1920 to construct aircraft engines. The new company was called Mitsubishi Heavy Industries (MHI), and it was the largest privately-held company in Japan. It concentrated mostly only aircraft, ships, and railroad cars, but in 1937 it introduced the prototype sedan PX33, which was designed for military use. It was also the first Japanese-built passenger car with full-time four-wheel drive.

After the end of World War II, MHI returned to manufacturing vehicles, including the production of Fuso busses, a three-wheeled cargo vehicle called the Mizushima, and a scooter called the Silver Pigeon. However, the Allied powers ordered that Japan's family-controlled industrial conglomerates be dismantled, and MHI was divided into West, Central and East Japan Heavy-Industries in 1950.

In 1951, East Japan Heavy-Industries began importing the Henry J, an knockdown-kit (CKD) American sedan built by Kaiser Motors. That same year, Central Japan Heavy-Industries formed a similar contract with Willys for the CKD-assembled Jeep CJ-3B, which led to licensed Mitsubishi Jeeps remaining in production until 1998.

By the 1960s, with a greatly improving Japanese economy, Central Japan Heavy-Industries, which had changed its name to Shin Mitsubishi Heavy-Industries, had already re-started their automotive department, and was ready to release the Mitsubishi 500, a mass-market sedan, it followed this with the Minica kei car in 1962, and the Colt 1000 - the first Colt - a year after that. Meanwhile, West Japan Heavy-Industries (which was renamed Mitsubishi Shipbuilding & Engineering) and East Japan Heavy-Industries (renamed to Mitsubishi Nihon Heavy-Industries) had also expanded their automotive departments, and in 1964 the three were reunited as Mitsubishi Heavy Industries.

Within three years the new MHI's output was over 75,000 vehicles per year, and, with the successful release of the 1969 Galant, and similar growth in its commercial vehicle division, it formed Mitsubishi Motors Corporation, on April 22nd, 1970. In 1981, Mitsubishi Motors North America (MMNA) was formed after tensions arose with MMC's American import partner, the Chrysler Corporation over the international subcompact market.

Since then, Mitsubishi has faced some troubles in the United States, but it is now re-energizing the brand. New model introductions have had mixed success, with the Outlander and Eclipse showing growth over 2005 but the Endeavor SUV failing to meet expectations. A new Lancer compact car is to debut in 2007, and the company is seeking new export markets for a redesigned Galant.