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She rose through the ranks to become the highest-ranking woman ever to serve at the Department of Defense.

She was also the inspiration for actress Kelly McGillis' role as a teacher named Charlie in the 1986 movie "Top Gun," which co-starred Tom Cruise.

And this week, Christine Fox, who was the acting deputy secretary of defense and a 1980s' flight school instructor, retired from the Pentagon.

President Obama acknowledged Fox's "dedicated service to our nation and to the men and women of our Armed Forces," adding in a statement that he was "grateful to Christine for her willingness to step in and serve her nation once again, as the highest ranking woman ever to serve at the Department of Defense."

Fox served as head of the Pentagon's Cost Assessment Program Evaluation office for more than three years. Her task was to oversee Pentagon decision-making on military spending and weapons programs.

Defense Secretary Chuck Hagel asked her in December to serve as acting deputy secretary until he found a replacement. He called Fox a "brilliant defense thinker and proven manager" who "knows the intricacies of the department's budget, programs and global operations better than anyone."

Fox became well-known after the "Top Gun" release.

She helped McGillis prepare for her role even though Fox told People Magazine in an interview back then: "My actual job has much more to do with the guy in the back seat of the plane, the radar-intercept operator, than the guy in the front, the pilot.

"I don't know anything about flying airplanes, but I know a lot about the guy in the back seat; his mission, his radar and his missiles."