In June 1957 the design of G-159 was finalised and Grumman started selling slots on the production line at $10,000 each.

The Gulfstream I is a low-wing cantilever monoplane with a semi-monocoque aluminium alloy fuselage structure.

The aircraft is powered by two Rolls-Royce Dart turboprops with Rotol four-bladed constant speed propellers.

The cabin is designed to take up to twenty-four passengers in a high-density arrangement or only eight in an executive layout, although ten to twelve was more usual.

A single Gulfstream I was delivered to the United States Coast Guard (USCG) in 1963, outfitted as an executive transport and designated the VC-4A.

Royale Airlines also operated the G-I in scheduled passenger service in the U.S. operating as Continental Connection on behalf of Continental Airlines; however, its aircraft were standard length G-159 models and thus were not the stretched version.

Air carriers in Africa, Canada, Europe and the Mideast also operated standard Gulfstream Is in scheduled passenger service, including Peregrine Air Services in the U.K., which operated airline flights for British Airways.

NASA, the U.S. space agency, flew the Gulfstream I as a passenger transport aircraft and operated seven G-Is.