The Naval Security Group Activity (NSGA) Key West was originally established in 1962, operating from a bunker at the eastern end of Naval Station Key West—now known as Naval Air Station Truman Annex. At its peak, the command consisted of roughly 500 sailors and marines.

In 1967, the Activity was deactivated, and its missions and functions were transferred to NSGA Homestead, Florida. Seven years later, in 1974, the Naval Security Group Detachment (NSGD) Key West—operating under Homestead—was reactivated on the west end of Truman Annex, directly across from President Truman’s “Little White House.”

On May 1, 1981, NSGA Key West was recommissioned as an echelon III command. Renovations to Building 1279 were completed by July 15, 1981, followed by the activation of communications circuits on October 22. Army and Navy operations began on October 27, with the Air Force joining on November 1. By December 18, 1981, all mission systems and antennas were fully operational.

When Hurricane Andrew devastated South Florida in August 1992—destroying Homestead Air Force Base and much of the surrounding area—the decision was made to decommission NSGA Homestead and transfer most of its mission to Key West. This transition sparked rapid growth, and by July 1993, the Key West command had more than doubled in size, marking a new era in its storied history.