Holsinger served for twenty-six years in the United States Department of Veterans Affairs (VA) from 1969 to 1994. He served at five different hospitals, rising to become a Medical Center Director. In 1990, President George H. W. Bush appointed Holsinger as Chief Medical Director of the VA (title changed to Under Secretary of Veterans Affairs for Health in 1992). He implemented the joint VA and Department of Defense Contingency Hospital System, which could provide 25,000 beds within seventy-two hours for soldiers fighting in Kuwait during the first Iraq War. He oversaw the nation's largest health care system, which served one million in-patients and twenty million out-patient visits per year. Holsinger also developed health care policy for twenty-six million veterans.