The Rainier was introduced on July 28, 2003, for the 2004 model year, in a 5-door, 5-passenger configuration, yet was one of only five GMT360 SUVs to offer a V8 engine — along with the GMC Envoy Denali, Isuzu Ascender EXT, Saab 9-7X 5.3i and Aero, and Chevrolet TrailBlazer LT (optional) and SS.

An available Sun, Sound and Entertainment package for 2005 (previously called CXL Plus,) added a power sunroof, better Bose stereo, and XM Satellite Radio.

GM ended production of the related Chevrolet TrailBlazer, GMC Envoy, and Saab 9-7X after the 2009 model year.

The Rainier's interior and options list is directly carried over from the Bravada, with only a silver faced gauge cluster with ice blue needles (and a cluster font similar to the Rendezvous CUV,) along with a Buick Tri-Shield emblem adorning the steering wheel.

In 2012, General Motors had recalled more than 258,000 SUVs in the U.S. and Canada to fix short-circuits in power window and door lock switches that could cause fires.

The recall covered Chevrolet TrailBlazer, GMC Envoy, Buick Rainier, Isuzu Ascender, and Saab 9-7X SUVs from the 2006 to the 2007 model years.

The SUVs were sold or registered in 20 U.S. states, Washington, D.C., and in Canada, where salt and other chemicals are used to clear roads in the winter.