He served as a pilot in the Air Force from 1965 to 1966, then attended graduate school at Georgetown University in International Relations.

During a succession of progressively responsible assignments in DE, Nagy focused on Soviet strategic nuclear and space forces and on policy and doctrinal issues; he was the principal drafter of numerous departmental and national estimates.

In late 1980, Nagy became a DIA executive and was selected to be the first deputy vice director for overall management of program development for estimative, basic, and scientific and technical intelligence production.

In this capacity, he held the position of chief of the Directorate for Research (DB), DIA’s largest single military intelligence production organization.

As acting director, he provided continuity during a critical time when decrements against Agency resources caused reconsideration of many managerial issues and review of traditional threat priorities throughout the Defense Intelligence Community.