 Cooke had a federal government career of more than 45 years in the Pentagon from 1957 to 2002. Notable positions he served in include Deputy Assistant Secretary of Defense for Administration from 1971 to 1988, Director of the Washington Headquarters Services since 1977, and Director of Administration and Management in the Office of the Secretary of Defense since 1988.Cooke was involved with Defense Department management issues since 1958, when he served on Defense Secretary Neil McElroy's task force on Department of Defense reorganization.He served under Defense Secretary Robert McNamara and helped institute changes in departmental management.