Hummers were traditionally built by AM General Corporation, formerly the heavy industries division of American Motors, in its Mishawaka, Indiana assembly plant. AM General had planned to sell a civilian version of the Hummer as far back as the late 1980s. In 1990, two matching white Hummers were driven from London, UK to Beijing, People's Republic of China over the rough roads of the central Soviet Union. The Hummers made the drive with ease, and highlights of this journey were broadcast on ESPN in the United States. The publicity would pale in comparison to the attention that the HMMWV received for its service in Operation: Desert Storm the following year.

In 1991, AM General began selling a civilian version of the M998 High Mobility Multipurpose Wheeled Vehicle (HMMWV or Hum-Vee) vehicle to the public under the brand name Hummer. In 1999, AM General sold the brand name to General Motors but continued to manufacture the vehicles, which GM then re-sold. In the next few years, GM introduced two new homegrown models, the H2 and H3, and renamed the original vehicle to H1. AM General continues to build the H1 and is contracted by GM to produce the H2. The H3 is built in Shreveport, LA.

As of 2004, Hummer has gone international with selected importers and distributors in Europe and other markets. It has only been sold in small volumes, but some celebrities and business people have bought Hummers to satisfy their curiosity. Markets such as Australia have taken interest to Hummers with importers converting the latest H3 to right hand drive despite GM not officially selling the brand in Australia.

From 2006, GM will be building/assembling the Hummer H3 at the Port Elizabeth plant in South Africa to make Hummers internationally available. Hummers at the Port Elizabeth plant will be built for local South African consumption and exported to Australia, the United Kingdom and Japan.

Evaluation

The first two Hummer models are large, heavy vehicles with large engines and complex drivelines. The third one, the H3, is smaller and geared more towards people who want an everyday SUV. They also feature aggressive styling and advertising, setting them apart from competing models. This has made them a target of criticism, as many people view Hummers as ill-suited for use as a passenger vehicle on public streets. As fuel prices have risen, detractors have also singled out the Hummer as an egregious waster of resources—a charge based largely on the Hummer's image.

Since both the H1 and H2 can weigh over 8,500 lb (GVWR), the United States fuel economy regulations do not apply to them. GM does not disclose their expected fuel economy ratings, and the company is not required to display a Monroney sticker on the vehicles. However, expected mpg ratings can be derived from their fuel capacity and range ratings. These metrics show that the Diesel H1 is expected to reach 16 mpg (U.S.), while the H2 should get 9.6 mpg. Car and Driver magazine observed 12 mpg with their H2 SUV. These ratings are similar to those of other heavy trucks and SUVs.