Replacing the Monaco, the St. Regis was the largest Dodge sedan, positioned above the mid-size Diplomat and Aspen.

Deriving its name from a 1950s Chrysler trim package, the St. Regis was the first example of downsizing of the full-size Dodge sedan line.

As Chrysler needed to expedite a downsized replacement for the 1974-1977 C-body to market (in response to the 1973 oil crisis), the R-body was developed from existing underpinnings at minimal costs.

In place of redesigning the full-size C-body, Chrysler developed the R-body as an update of the intermediate B-body (last released in 1971, dating to 1962).

The Chrysler R-body cars (like their 1974–78 predecessors) arrived at precisely the wrong time, as a second gasoline crisis hit the U.S. in 1979.

In contrast to the clean-sheet Ford and GM designs, the dire financial situation of Chrysler relegated the company to retool an existing chassis.

Coinciding with its usage in law enforcement, the St. Regis appeared on multiple 1980s police-based television series, including Sledge Hammer!, The A-Team and T.J. Hooker.

While the St. Regis is of little collector value today (alongside Chrysler/Plymouth R-body counterparts), the mechanical commonality of the R platform with earlier Chrysler vehicles leads collectors to search for scrapped examples for its front disc brakes to upgrade earlier cars (such as the Dodge Dart and Plymouth Barracuda)[citation needed] With the low number built (in comparison to its Ford and Chevrolet competitors) and the high percentage destroyed in film and TV work or retired after police use, very few examples survive today.