The Legacy was introduced in 1989 to provide Subaru with a vehicle to compete in the lucrative North American mid-size market against the Honda Accord, Toyota Camry, Mazda 626, and Nissan Stanza. It was an all-new model, and positioned above the Leone, XT, Justy, and kei cars Rex and Sambar in Subaru's model range at the time. The Legacy also introduced an entirely new flat-4 engine series, called the EJ.

The Legacy began with a 5-door wagon or 4-door sedan body styles with FWD and an optional full-time AWD package, and was introduced in North America, the UK, Germany, the Benelux region of Northern Europe, Japan and Australia. It was formally released January 23, 1989 in Japan, with worldwide distribution starting in 1990.

Vanguards modelled the first generation car marketed from 1989 to 1994.