[3][4] Hidalgo previously served as Assistant Secretary of the Navy for Manpower and Reserve Affairs from April 1977 to October 1979.

The family moved in 1918 to the United States and settled in New York City,[2] where he became an American citizen and anglicized his name to Edward.

[6] Hidalgo was educated at the College of the Holy Cross, where he was a member of the debate team,[7] graduated magna cum laude in 1933 as class salutatorian, and delivered a salutatory address titled "Peace among Nations.

From 1965 to 1966 he served as Special Assistant to the Secretary of the Navy, Paul H. Nitze, and then resumed legal work from 1966 to 1972 as a partner in the law firm of Cahill, Gordon & Reindel, in charge of their European office.

[10] In 1972 he left the firm to resume government service as Special Assistant for Economic Affairs to the Director of the US Information Agency.

[citation needed] Hidalgo served from April 25, 1977, as Assistant Secretary of the Navy (Manpower, Reserve Affairs and Logistics).