A native of Medina, Ohio, Hamby was commissioned from the University of North Carolina at Chapel Hill Navy ROTC program in 1980. Early assignments included duty at Naval Regional Data Automation Center, Washington, and commander, Naval Base Pearl Harbor and plans and project management department head at the Data Processing Service Center, Pearl Harbor. She attended Boston University earning a Master of Science in Information Systems Management and a Master of Business Administration, graduating from both programs with highest honors. She was subsequently assigned as assistant professor of Computer Sciences at the U.S. Military Academy and then served as deputy director of the Communications Operations Directorate at Naval Computer and Telecommunication Station Washington. In 1994 she reported to USS Dwight D. Eisenhower (CVN 69), as part of the initial assignment of women to naval combatants. She participated in Eisenhower’s deployment to Haiti in support of Operation Uphold Democracy completing her surface warfare qualification during Eisenhower’s 1994 Mediterranean deployment. In August 1995 she transferred to USS George Washington (CVN 73) to serve as the first afloat combat systems officer to combine information systems management, combat systems maintenance and telecommunications systems management in one department.

Hamby graduated from the U.S. Naval War College in November 1997, earning a Master of Arts in National Security and Strategic Studies. Awarded the Vice Adm. Arthur Cebrowski award for best essay related to information warfare, command and control warfare and related systems and technology issues, she graduated with distinction and was named Presidential Honor Graduate. Hamby was then selected to serve as an associate fellow on the chief of Naval Operations’ Strategic Studies Group.