He was best known for:
* Developing the Luft Doctrine: A theory of intelligence analysis that focused on understanding the adversary's decision-making processes. This doctrine became widely influential and is still used by intelligence agencies today.
* Working on "The Pentagon Papers": Luft was one of the analysts involved in preparing the classified study of US decision-making in the Vietnam War that was later leaked to the New York Times, becoming known as "The Pentagon Papers."
While he didn't hold a specific civilian job, his work in the military significantly shaped the field of intelligence analysis.