The fourth generation of the Subaru Legacy was introduced in 2003 and saw a complete redesign of the Legacy on an all-new platform. Development began by the beginning of 1999, with styling freeze in early 2001 and engineering sign-off in 2003.

The fifth-generation Subaru Legacy was originally unveiled as a concept car at the 2009 North American International Auto Show in Detroit to commemorate the 20th anniversary of the model, and the production version was introduced at the 2009 New York International Auto Show. Production of the fifth generation started on 29 May 2009.