The first generation of the car, initially known as the Colt Galant, was released in December 1969. Three models were available, powered by the new 'Saturn' engine in 1.3 (AI model) or 1.5L (AII and AIII) configurations. The design was dubbed "Dynawedge" by Mitsubishi, referring to the influence of aerodynamics on the silhouette. Initially only available as a four-door, a two-door hardtop variant was added in 1970, offering the unique stylistic feature of being the first Japanese production passenger car with full side windows and no side pillars. It became Mitsubishi's first car to be sold in the United States in 1971 when the Chrysler Corporation, the company's new partner and stakeholder, began importing the car as the Dodge Colt.
From 1970, a fastback coupé model was developed, the Galant GTO. Fashioned after contemporary American muscle cars, the hardtop GTO was available with a choice of three 4G32 'Saturn' engines, and was available until 1975. The nameplate was sufficiently highly regarded in Japan for it to be resurrected for the 1990 Mitsubishi GTO coupé.