Ruina received his Doctor of Philosophy degree in electrical engineering from the Poytechnic Institute of Brooklyn, He then served in positions at the United States. Department of Defense, including deputy for research to the assistant secretary of research and engineering of the United States. Air Force, Assistant Director of Defense Research and Engineering for the Office of the Secretary of Defense, and Director of the Advanced Research Projects Agency.
From 1966 to 1970, he was also vice president for special laboratories at Massachusetts Institute of Technology. In 1962, he was honored with the Fleming Award for being one of ten outstanding young men in government. From 1964 to 1966, during a two-year leave of absence from Massachusetts Institute of Technology, he served as president of the Institute for Defense Analysis in Arlington, Virginia. While at Massachusetts Institute of Technology, Ruina served on government committees, including a presidential appointment to the General Advisory Committee from 1969 to 1977, and acting as senior consultant to the White House Office of Science and Technology Policy from 1977 to 1980.
He was an honorary member of the Board of Trustees of the MITRE Corporation, and the editor with Jeffrey Porro and Carl Kaysen of the book The Nuclear Age Reader (1988).
